Images are made up of 3 channels of red, green and blue pixels, each with its own brightness level. Brightness of 0 in all channels gives black; Brightness of 255 in all channels gives white. In post processing, simplistically, we can adjust the pixel values across the image to make the image brighter (increased exposure) or darker (decreased exposure) or adjust the balance between dark and light pixels (contrast).
Lets look at an example. In the image below the left column shows the image. On the right are histograms showing the distribution of dark (to the left) and bright (to the right) pixels. In the middle row you can see from the histogram that the brightness levels are spread all the way from black to white. There is a hump towards the right because there is a large area of fairly bright sand in the image. With underexposure (top row), the histogram is skewed to the left, detail is lost in the shadows, and the image looks dull. Overexposure (bottom row) shifts the histogram to the right. The image looks washed out; detail is lost in the highlights, and the dark fur looks grey rather than black.
Contrast relates to how broadly the pixels are distributed in the histogram. If the contrast is too low the image will look muddy and there will be few if any pixels at the extremes of brightness and darkness. If contrast is too high the image will look harsh, with loss of detail in the highlights and shadows and most of the pixels are distributed to the extremes of lightness or darkness.
Fortunately, image processing software allows you to easily adjust the exposure and contrast. The basic edit controls from the Lightroom develop module show the Exposure and Contrast sliders along with several other sliders that give you a great deal of fine control. Most software has similar controls available. What do they all do? The best idea is to take an image and play with the sliders to see what the effects are.
Exposure: adjusts the overall brightness
Contrast: spreads out (slide to right) or centralises (slide to left) the tones in your image.
Highlights: adjusts only the brightest areas. Use this to bring back lost detail in bright areas
Shadows: adjusts the darker areas and can bring back detail in the shadows
Whites: adjusts the white point of the image. Moving this slider to the right makes white tones brighter. This control affects the whole image though the effect is most obvious in the light areas.
Blacks: adjusts the black point. Moving this slider to the left can move the dark areas further towards black. This control affects the whole image but the effect is most pronounced in the dark areas.
Presence: the controls in this section work in various ways to bring out detail (slide to the right) or reduce detail (slide to the left). They can make your images pop. Experiment to find what they do.
Luminar 4 – essential edits
To the right is one of the editing panels from Luminar to show that the same sorts of basic controls are present – colour balance, exposure, contrast, highlights, shadows, whites and blacks. Other panels cover a suite of other adjustments. Topaz and Affinity have similar basic edit panels.
Further Resources
Here are some links to resources that explain more fully the editing controls and strategies to adjust your image. Some of the links also cover colour balance, cropping etc.
There are lots of packages available, some expensive/subscription, some free. All have pros and cons in terms of features and ease of use.
Tim Keane has made a brief comparison of Photoshop, Photoshop Elements, Lightroom and the free MS Photo.
Another good resource, that John Morter has pointed me to, is the “Life after Photoshop” website. It seems to have a good selection of reviews, and lots of tips and tutorials on various software packages. Some of the reviews (eg this one) provide side-by-side comparisons of the performance of the various packages with a range of sometimes challenging images. A caveat with reviews is that the developers are constantly improving the software, so it is important to check the dates on the reviews or that the reviews are for the current software versions. The Life after Photoshop site seems to be actively developed, and many of the pages are up-to-date.
Besides these, other software commonly used by photographers for image manipulation includes (among others see HERE for a range of other software) DxO Photolab, Topaz Studio, Affinity Photo, Luminar, Paintshop Pro, Exposure X6 and open source and free applications like GIMP, Dark Table, Raw Therapee, Krita and Photopea. Many of the paid software makers offer free trials so you can spend some time assessing and comparing the packages. Some packages have particular strengths or functionality that is not present in the other software. There is no need to restrict yourself to just one. Many of them also provide plug in functionality that allows, say a Lightroom user to directly send an image to, say, Luminar or Topaz or Affinity Photo, and place the edited file back in the LR catalog after your edits in the other program are done. Alternatively you can edit in one package, and save to a TIFF that you can open and edit in a different package to take advantage of the differing tools and functions of the various programs.
Some of these programs provide file management (also referred to as digital asset management or DAM) as well as image editing. File management can be a great boon allowing you to find images down the track. If your selected editing software does not provide this function I recommend you explore a file management package to complement it. Adobe Bridge (free) has some powerful functions, allows you to preview, rate, add keywords, manipulate file metadata, and open files with editor programs. There are many other packages to consider – https://en.wikipedia.org/wiki/Image_organizer gives a good overview, as does the digiKam documentation at https://docs.kde.org/trunk5/en/digikam-doc/digikam/using-dam.html.
No matter what software you use, take some time to read the documentation and learn how to use the software. If the software includes file management, then it is sensible to use these functions if you want to reorganise your files, especially for packages like Lightroom, where the catalog contains information about where files are stored. If you move files using your operating system file management, Lightroom will no longer be able to find your files until you tell it where they have gone.
As Lightroom and Photoshop are the most commonly used software for image editing, these feature in the examples in this website. However usually the general principles will apply to other software packages, though with different user interfaces.
Note that RAW image processors work in a non-destructive editing paradigm, saving the editing steps in a database or sidecar file so when you open the RAW file, your software uses the editing steps to recreate the final edited image. This does not mean these editing steps are compatible between software packages. Different programs use different underlying maths to make the edits and may have different editing filters, so you cannot make a non-destructive switch of edits from one package to another.
I have outlined some of the available packages below. These are very brief outlines of these applications as I experienced them. These are not detailed reviews. For most, I have a second page focusing in more detail on a single application, You can also search the internet for up-to-date detailed reviews (but beware, some reviews can be biased because some web authors get paid to be nice to some vendors).
Lightroom incorporates extensive file management capability with excellent image editing and a non-destructive workflow.
Available together in the Adobe CC Photography plan for a monthly/yearly subscription, this is the most commonly used photo management and editing software and has a wealth of online resources. It has amazing tools and a good user interface. For many users Lightroom alone gives them powerful image management and editing workflows with an effective user interface. Photoshop adds huge creative power to image manipulation (at the expense of complexity and a lot of learning how to use it). It is easy to flip images from Lightroom to Photoshop for more complex edits, then return the edited image to Lightroom for further editing or file management. I will assume the use of the desktop versions of these applications rather than the mobile or cloud based variants in my descriptions of how to use the programs in this website.
Photoshop goes beyond Lightroom’s image editing potential with extensive processing filters, layers and masks and ability to easily combine and blend different images
Many people dislike the subscription payment model. Adobe CC photography plan (includes Lightroom+Photoshop) is currently (2021) about AU$14.25 per month. However, compared to the typical investment in cameras, lenses, filters, lighting, bags and other accessories, SD/CF card media, computers, monitors, printers, backup drives, insurance … the annual subscription cost of the Adobe software (which provides continuous access to all the updates) isn’t overwhelming. Nevertheless, there are many viable alternatives out there for free or reasonable one-off cost for a perpetual license.
You can download Adobe’s flagship desktop media browser and digital asset manager for free, and it works fine as a standalone application. You can use it to browse and organise your image library. You can add keywords, rate images etc etc. Whilst it had no built in image editing capabilities, you can open image files in the editor of your choice (default is Photoshop, of course). You can download from Adobe at https://www.adobe.com/au/products/bridge.html. There are guides on its use at https://helpx.adobe.com/au/support/bridge.html.
Adobe Camera Raw (ACR)
Surprisingly, Adobe make ACR free to download as part of the Adobe Bridge package. It is the same engine used for RAW processing in Lightroom and Photoshop, and has a wealth of capabilities in processing RAW files that you can then save as PSD, TIFF, JPEG etc.
Free and powerful/ Windows. OSX, Linux. Similar to Photoshop in what it can do. Huge numbers of add-ons to add filters etc. User interface not as sleek, and needs an added (Free) package (eg RawTherapee, UFRaw or DarkTable) to open Raw files. However if you can spend a little time to install GIMP and learn the ropes, you will have a very powerful, very flexible and very extensible image editor for an unbeatable price. I have made a page with more details; or go to the GIMP home page https://www.gimp.org/
Another free and powerful application for Windows. OSX, Linux. Raw Therapee is to Lightroom what GIMP is to Photoshop. It provides outstanding raw file editing but, at present, no local adjustments. File management includes sorting and filtering based on metadata, rating and colour labels, though the digital assets management functionality is much less than LR provides. More HERE.
Darktable is another free, open source application available for Windows, OSX and Linux. It has file management with filtering and sorting, keyword tagging and metadata editing, a powerful non-destructive image editing workflow (for both RAW and non-raw formats) with a comprehensive array of adjustments available. It also has local editing /masking. See HERE for some more information.
LightZone is a free open-source photo editor with an emphasis on workflow. It provides a non-destructive editing of a variety of RAW formats (it can also handle non-RAW formats like TIFF and JPEG). In many ways it is similar to Lightroom (but free). Versions are available for Windows, MacOS and Linux.
It has a similar workflow paradigm to Lightroom. It has file management functions, and metadata editing (limited; no keywording supported) as well as editing adjustments, masking etc.
You can get a good idea of the User Interface by browsing the LightZone screenshots.
Lightzone Editing screen. Note the extensive list of “styles” on the left – these add filters with sliders to modify the effect into the processing sequence on the lower right below the histogram.
This is a community based project, so don’t expect as complete a level of documentation as you might with some other software, but the community is available online to provide answers to all your questions.
Krita is a free and open source graphics editor for Windows, Mac OS and Linux. It is designed primarily for graphic artists for digital painting and 2D animation, but it is also a competent editor for photos.
It supports layers (including non-destructive filter layers), layer blending modes and effects, masks and so on. See HERE for a bit more detail.
Powerful filters, layers, masks. Presets for easy automated global changes. Unique AI based tools. can add textures with blending modes, and composite different images. Automated sky replacement. File management including Albums. One-off purchase (unless you upgrade to a newer version). Luminar (https://skylum.com/). Plugins to allow it to be used with some other software. Extensive training resources and online manual. Luminar 4 has a full layering system. Luminar AI uses sophisticated AI approaches in its adjustments. It does not have explicit layers, but there is flexible masking for applied adjustments. More detail HERE.
Powerful filters including some unique AI based tools, layers, masks. One-off purchase (unless you upgrade to a newer version). https://topazlabs.com/ Standalone or plugin. A more detailed post is HERE.
Basic file browser with indexing of photos; virtual image copies; images can be organised by Projects; star rating; no support for keyword management and other digital asset management functions. Powerful filters, layers, masks. Collections of preset edits to quickly try and modify. One-off purchase (unless you upgrade to a newer version). https://www.dxo.com/dxo-photolab/ Standalone or plugin. A post with more information is HERE.
Powerful filters, layers, masks. Compositing, Powerful Raw file editing; PSD editing and smart object support. Retouching tools; content aware in-painting brush; HDR and focus stacking; It lacks digital asset management, and doesn’t appear to allow a non-destructive raw workflow (it does not save the edits in a sidecar file or database – you edit and save an output file, so if you want to re-edit the raw file, you start again from scratch – I think some edits may be saved in layers in an output PSD or TIFF file) – One-off purchase (unless you upgrade to a newer version). affinity. https://affinity.serif.com/en-gb/photo/.
Capture One started life as software to support Phase One’s high-end digital cameras, in particular in tethered image capture situations, but is now available for most makes. It is a superb professional Raw image processor. It is feature rich, with a layered image processing model. It has image management/cataloging functions, though not as good as Lightroom’s.
Another up and coming contender is On1 Photo RAW. It has a well featured package with digital asset management (DAM: photo organisation, cataloguing, rating etc) as well as extensive image editing capability. Some more information on a more detailed post HERE.
A powerful Photoshop-like photo editor that lives in your browser. Photopea is a powerful photo editor that’s a progressive web app. You can make edits to photos, enhance them, and use both vector and raster tools all without having to download a thing. I’ve written more info HERE.
I haven’t used Exposure hands-on but I have made some notes on a post HERE.
It has some Digital Asset Management functions allowing you to effectvely browse and catalogue your images. It has a flexible layer/masking system for filters/effects, but lacks image layers so it isn’t so good for compositing.
Originally developed by Jasc Software and purchased by Corel in 2004, PaintShop Pro is a full-featured image editor for Windows (not MacOS version . I have not used it, so the following notes are based on the documentation on the PaintShop website.
It reads a wide variety of RAW file formats. It has: file management functions; a clear and customisable workspace; tools for a wide range of image adjustments; local adjustments; layers and masks and compositing; sophisticated selection tools; HDR merging; Photoshop Plugin compatibility (ie you can use PS plugins; and you can use it as a plugin in PS); and lots more. Like most modern packages there is a lot of AI built in to the processing filters.
Another package I have not tried hands on, but the blurb on their page tells that it has digital asset management, support for a wide range of RAW formats and comprehensive RAW editing tools, sophisticated processing filters, layered editing, colour/tone adjustment tools, HDR and focus stacking, retouching tools and more. There seems to be a lot of tutorials, online and downloadable user documentation (PDF or online), and other support materials on their site. They have a comparison table that is perhaps a little biassed (eg they claim LR costs $79.49 per month, not $15, and forget the tools in Photoshop that come with the LR/PS photography bundle; they claim PaintShop Pro lacks Spot/Dust removal – it does (but they call them content aware editing tools) –so take their comparisons with a large grain of salt). They offer a free trial, so you can have a play to see if it suits your needs.
OTHER
Please let me know if you would like me to add/review any extra software for this list
If you have two monitors, images will look similar on both
if you share an image with someone else, they are likely to see something similar to what you see on your monitor (assuming they have calibrated their monitor)
If you print to a calibrated printer the prints will look as similar as possible to what you see on screen
The best way to calibrate a monitor is to use specialised calibration hardware from Datacolor or X-rite or others, but you can do a fairly good job using facilities built into Window 10. Tim Keane has made a brief guide to this process HERE.
A triptych is a work of art divided into 3 sections. This approach allows the creator to tell a story that would be difficult with just a single panel. Below is a fine example: The three panels of the triptych tell a powerful story of a free selector, a farmer who has chosen some land to clear and farm, and his family. You can apply the same approach to story telling using your photographic images. You might want to show a story through time (as below) or place, or the development of an artistic image using 3 different variations … the options are endless so use your imagination.
Tim Keane has made a basic introduction to creating a Triptych that you can download HERE. This guide is based on Photoshop/Photoshop Elements but the general principles apply whichever software you use (so long as the software allows combining multiple images into one). I have made some alternative instructions HERE based on Lightroom (easy) and on Photoshop (a bit more challenging). If you use other software, you may need to adapt these approaches, or seek alternative resources online.
Using Photoshop or equivalent is the most powerful way to make a Triptych, but if you don’t have access to suitable software, you can even use presentation software such as Libre Office Impress (free) or Microsoft Powerpoint (part of the MS Office suite). These packages give you a great deal of flexibility in placing, shaping and aligning images. Afterwards, you can export to JPEG at high resolution. Since these programs are based on units of pages, you will probably need to open their output in a photo editing program and crop the unused parts of the page layout to get the final output.
If you use Lightroom, you can use the PRINT module to generate your layout. In the Gallery module select 3 images (you can set up a collection to contain your images so they are all in one place). Then switch to the PRINT module. Set the page size appropriate for your needs (menu: File >> Page Setup). You can choose from a range of pre-defined page sizes, or choose a PDF custom page size, that you can define in the PDF print setup dialog. Then, in the Layout Style (right hand column) choose Single Image/Contact Sheet. In Layout choose page grid 1 row, 3 columns. Adjust the cell size to suit (unclick the Keep Square box if it is ticked), or drag the guides on the central page layout panel. If you want the separate panels to be outlined, say in black, check the Stroke Border setting in the Image Settings panel. Check the PrintJob panel (bottom on right) says Print to: JPEG File. Then choose File >> Print to output the JPEG file. You may need to resize this, depending on the settings and sizes on the layout. If you set File Resolution to a high number you will have plenty of pixels so you don’t lose quality in a later resize. If you want to make a layout with unequal sized panels for you images, you will have to use the Custom Package in the Layout Style, and then add and resize the components individually. You can save your layout as a template. In the Template Browser, click the PLUS sign to add a new template with your current settings.
With Photoshop you can easily create triptych layouts with the images in layers, and using masks and layout guides (menu: View >> New Guide Layout) to assist with layouts. There are many instructional guides on the web. Here are a few:
When you have multiple layers in your image, you can use blending modes to alter how the different layers interact to produce the final effect. The brief description below is based on photoshop, but if you use other software that has layers and masks, it will probably also have blending modes that work in similar ways and probably have similar names.
Blending modes apply to layers, but can equally apply to edit tools like the clone brush. For example you can set the clone tool options to, say, darken, so when you use the brush, it will only clone over the areas where the target area is lighter (able to be darkened) than the source.
on the left I have used a clone tool to hide the forehead wrinkles using a normal blend mode. On the right using a Lighter colour blend mode. Here only the darker core of the wrinkle is overlaid by the clone stamp, reducing the artefacts like repeating patterns. I have used layers to hold the repairs (non-destructive editing), but I could equally have used the clone stamp on the background layer, with the blend mode applied to the tool as I applied it.
Here is a somewhat technical synopsis of the Blending Modes mostly from the Adobe website.
Normal Blending Modes
Normal
Edits or paints each pixel to make it the result color. This is the default mode. (Normal mode is called Threshold when you’re working with a bitmapped or indexed-color image.)
Dissolve
Edits or paints each pixel to make it the result color. However, the result color is a random replacement of the pixels with the base color or the blend color, depending on the opacity at any pixel location.
Darken Blending Modes
Darken
Looks at the color information in each channel and selects the base or blend color—whichever is darker—as the result color. Pixels lighter than the blend color are replaced, and pixels darker than the blend color do not change.
Multiply
Looks at the color information in each channel and multiplies the base color by the blend color. The result color is always a darker color. Multiplying any color with black produces black. Multiplying any color with white leaves the color unchanged. When you’re painting with a color other than black or white, successive strokes with a painting tool produce progressively darker colors. The effect is similar to drawing on the image with multiple marking pens.
Color Burn
Looks at the color information in each channel and darkens the base color to reflect the blend color by increasing the contrast between the two. Blending with white produces no change.
Linear Burn
Looks at the color information in each channel and darkens the base color to reflect the blend color by decreasing the brightness. Blending with white produces no change.
Darker Color
Compares the total of all channel values for the blend and base color and displays the lower value color. Darker Color does not produce a third color, which can result from the Darken blend, because it chooses the lowest channel values from both the base and the blend color to create the result color.
Lighten Blending Modes
Lighten
Looks at the color information in each channel and selects the base or blend color—whichever is lighter—as the result color. Pixels darker than the blend color are replaced, and pixels lighter than the blend color do not change.
Screen
Looks at each channel’s color information and multiplies the inverse of the blend and base colors. The result color is always a lighter color. Screening with black leaves the color unchanged. Screening with white produces white. The effect is similar to projecting multiple photographic slides on top of each other.
Color Dodge
Looks at the color information in each channel and brightens the base color to reflect the blend color by decreasing contrast between the two. Blending with black produces no change.
Linear Dodge (Add)
Looks at the color information in each channel and brightens the base color to reflect the blend color by increasing the brightness. Blending with black produces no change.
Lighter Color
Compares the total of all channel values for the blend and base color and displays the higher value color. Lighter Color does not produce a third color, which can result from the Lighten blend, because it chooses the highest channel values from both the base and blend color to create the result color.
Contrast Blending Modes
Overlay
Multiplies or screens the colors, depending on the base color. Patterns or colors overlay the existing pixels while preserving the highlights and shadows of the base color. The base color is not replaced, but mixed with the blend color to reflect the lightness or darkness of the original color.
Soft Light
Darkens or lightens the colors, depending on the blend color. The effect is similar to shining a diffused spotlight on the image. If the blend color (light source) is lighter than 50% gray, the image is lightened as if it were dodged. If the blend color is darker than 50% gray, the image is darkened as if it were burned in. Painting with pure black or white produces a distinctly darker or lighter area, but does not result in pure black or white.
Hard Light
Multiplies or screens the colors, depending on the blend color. The effect is similar to shining a harsh spotlight on the image. If the blend color (light source) is lighter than 50% gray, the image is lightened, as if it were screened. This is useful for adding highlights to an image. If the blend color is darker than 50% gray, the image is darkened, as if it were multiplied. This is useful for adding shadows to an image. Painting with pure black or white results in pure black or white.
Vivid Light
Burns or dodges the colors by increasing or decreasing the contrast, depending on the blend color. If the blend color (light source) is lighter than 50% gray, the image is lightened by decreasing the contrast. If the blend color is darker than 50% gray, the image is darkened by increasing the contrast.
Linear Light
Burns or dodges the colors by decreasing or increasing the brightness, depending on the blend color. If the blend color (light source) is lighter than 50% gray, the image is lightened by increasing the brightness. If the blend color is darker than 50% gray, the image is darkened by decreasing the brightness.
Pin Light
Replaces the colors, depending on the blend color. If the blend color (light source) is lighter than 50% gray, pixels darker than the blend color are replaced, and pixels lighter than the blend color do not change. If the blend color is darker than 50% gray, pixels lighter than the blend color are replaced, and pixels darker than the blend color do not change. This is useful for adding special effects to an image.
Hard Mix
Adds the red, green and blue channel values of the blend color to the RGB values of the base color. If the resulting sum for a channel is 255 or greater, it receives a value of 255; if less than 255, a value of 0. Therefore, all blended pixels have red, green, and blue channel values of either 0 or 255. This changes all pixels to primary additive colors (red, green, or blue), white, or black.
Note: For CMYK images, Hard Mix changes all pixels to the primary subtractive colors (cyan, yellow, or magenta), white, or black. The maximum color value is 100.
Inversion Blending Modes
Difference
Looks at the color information in each channel and subtracts either the blend color from the base color or the base color from the blend color, depending on which has the greater brightness value. Blending with white inverts the base color values; blending with black produces no change.
Exclusion
Creates an effect similar to but lower in contrast than the Difference mode. Blending with white inverts the base color values. Blending with black produces no change.
Subtract
Looks at the color information in each channel and subtracts the blend color from the base color. In 8- and 16-bit images, any resulting negative values are clipped to zero.
Divide
Looks at the color information in each channel and divides the blend color from the base color.
Component Blending Modes
Hue
Creates a result color with the luminance and saturation of the base color and the hue of the blend color.
Saturation
Creates a result color with the luminance and hue of the base color and the saturation of the blend color. Painting with this mode in an area with no (0) saturation (gray) causes no change.
Color
Creates a result color with the luminance of the base color and the hue and saturation of the blend color. This preserves the gray levels in the image and is useful for coloring monochrome images and for tinting color images.
Luminosity
Creates a result color with the hue and saturation of the base color and the luminance of the blend color. This mode creates the inverse effect of Color mode.
Extra Blending Modes for Painting Tools
Behind
Edits or paints only on the transparent part of a layer. This mode works only in layers with Lock Transparency deselected and is analogous to painting on the back of transparent areas on a sheet of acetate.
Clear
Edits or paints each pixel and makes it transparent. This mode is available for the Shape tools (when fill region is selected), Paint Bucket tool , Brush tool , Pencil tool , Fill command, and Stroke command. You must be in a layer with Lock Transparency deselected to use this mode.
Extra Blending Tools for Groups
Pass Through
For groups the default Blending Mode is not Normal, but “Pass Through.” This Blending Mode tells Photoshop to treat all the layers within a group as if they were just stacked and not part of a group. The group is useful for organisation and all the layers all blend as if they were not grouped.
However, if you changed the group’s Blending Mode say to Normal, Photoshop will first blend the layers in the group, then it will blend the resulting composite with the layers below it using the Blending Mode that you selected. Effectively this is the same as merging all the layers in a group and then applying that (non Pass-Trough) Blending Mode.
This is particularly useful when compositing. If set a Group’s Blending Mode to Normal, the adjustment layers inside of the group will only affect the contents of that group.
As the name suggests, masks are used to hide things. With a mask applied, you can limit what pixels in a layer are visible and allow you to make local adjustments using an adjustment layer. Masks are a fundamental tool in your post processing workflow.
Masks were covered briefly in the Basic Edits section, so here we will go into more depth. First we should understand alpha channels. You should be familiar with the Red, Green and Blue channels that combine to make the RGB composite layer. These are “opaque layers”. An alpha layer controls the transparency, making pixels see-through where the channel is black, partially transparent for shades of grey, and opaque where the channel is white.
Below is an image of an owl flying with blurred trees in the background. I have added a blue-yellow gradient in the layer below, and added a mask for the bird, and added a feathered black brush over the left side to show how greys allow partial transparency. Note that when the mask was added, a new channel was added (bird Mask). The channel itself is not visible, but its effect on the transparency of the layer is evident. If you click the eye icon to make bird Mask visible, it shows up as a red overlay (quick mask).
Masks apply equally to adjustment layers, where the adjustment can be removed totally (black) or partially (grey) using an adjustment layer mask. Feathering the mask can smooth the blending so that you don’t get sharp jumps at the edge of your adjustment mask. The same is true of pixel layers. Note in the example above the wing edges over the yellow are a bit abrupt. feathering the mask along that edge improves the blending.
How do you make a mask?
Mask from selection
If you have made a selection then click the layer mask button at the bottom of the layers panel, the selection will be converted to a mask, and the selection will be deselected. You can refine the mask made this way by painting over it (see below).
If your layer has a mask, you can turn that mask into a selection by holding control whilst left-clicking on the layer mask thumbnail in the layers panel (Mac: Command-click). You can therefore use a mask to store selections that you can later refine by adding or subtracting using selection tools, or by painting (see below).
Painting in a mask
The simplest approach to making a mask is to click the layer mask button at the bottom of the layers panel. A pixel mask will show to the right of the layer thumbnail. If you had a selection active, the mask will show the selection (white for selected, black for unselected, shades of grey where the selection was partial). If no selection is active, you will get a white mask thumbnail. Select this mask thumbnail and paint on the image window with black/white/gray using a paintbrush. Each time you end a paint sweep, the mask thumbnail will be updated, and the effect of the altered mask will show on the window. Press Q to activate quick mask mode where you can see the mask as a shaded red overlay over your image. Press Q again to turn off quick mask mode. Ctrl-click the mask thumbnail to convert the mask to a selection.
Set the brush to a low flow if you want to slowly build up the opacity with several sweeps of your brush. This can be good for making subtle gradations.
Use a black mask and paint where you want to show; or use a white mask and paint in black to hide parts. Select the mask thumbnail and press Ctrl-I to invert the mask. Use a large brush to block out the main areas for your mask Then switch brush colour (Black to white or vice versa – shortcut key X) and paint any overflow onto adjacent areas using a smaller brush with probably less feather, as required.
Select and Mask
The select and mask tool
If you have a selection tool active, then Select and Mask will be available on the options bar. Or you can activate it using the Select > Select and mask menu. Select and mask allows you to create refined selections using sophisticated tools.
In some cases you can effectively make selections. In the Layer Style dialog (double click a layer thumbnail). Using this, you can, for example, knock out the sky as if it were masked out – Use Blend-if, select blues, and adjust the sliders to make the blues in the sky transparent. This often overlooked tool can sometimes make quick work of what would potentially be tricky selections/masking. You can read more about it at https://digital-photography-school.com/photoshop-tips-blend-if-feature/ — I’ll get round to making a page at some stage.
A vector type layer remains sharp if it is enlarged (here by 500%) whilst a rasterized type layer looks fuzzy when enlarged by the same amount.
A raster layer contains pixels. These are the normal layers you use with photographic images. The resolution of the detail is determined by the pixels. If you transform, for example enlarging, the edges will get blocky or fuzzy depending on how your software interpolates new pixels. Raster layers contain geometrically defined shapes – for example a type layer, or a vector shape drawn with the pen tool in Photoshop. If you enlarge these, the edges remain crisp because the software uses the maths of the curves to generate new pixels according to the vector shapes.
If you are making composite images, the same issues can apply if you paste in parts from other images. If you shrink them, pixels are lost as it interpolates to the new size, then if you later enlarge them, your inserted image might appear fuzzy. If you want to avoid this, after pasting a new layer, in Photoshop convert the layer to a smart object. It will then retain full resolution internally, as you resize it. Photoshop will simply interpolate the appropriate pixels to show for the image resolution. If you resize, PS will make a new interpolation for show, whilst leaving the original image pixels unchanged.
Smart object layers for non-destructive editing
As noted, smart objects allow you to transform – scale, skew, distort, rotate or warp a layer without losing any of the original image quality. In addition, an adjustment applied to a smart layer does not change the original layer pixels, it just changes how those pixels are presented. If you want to view the results and change the filter settings, you can do so as many times as you like without accumulating artefacts as you would with a normal vector layer. You can even make linked copies of a smart layer – say you want 3 seagulls in the sky and you just have one seagull image to start with. Make it a smart layer, duplicate it twice. Reposition each seagull copy to a suitable location in the sky. Use transformations – warp etc. to change the shapes a little so they don’t look identical. Perhaps go back and tweak the distortions or the scaling. Photoshop internally only keeps one copy of the original seagull, and uses this for all 3 layers to apply the movements, and shape transforms to generate the final composition. Instead of your file containing 3 raster layers of seagulls, it only has one, which can save a lot of file size.
On the image above I have duplicated a smart layer to make 3 birds. Applied some transforms to alter the orientation and rotation, and also applied a puppet warp to change the shape of the wings on the layer Seagull Copy. Note that since this is a smart layer, the puppet warp shows up under the layer as a Smart Filter, so I could go back and tweak the puppet warp later if I am not happy with the shape of the wings or body.
Adjustment layers
Adjustment layers can be added using the adjustment layer tool at the bottom of the layers panel. Many adjustments are available to tweak the tonality and colour. The adjustment layer is added above the currently selected layer and by default applies to all the layers below. However you can limit the effect to just the layer immediately below by ticking the icon indicated by the “hand” cursor on the screen grab below, where I have added a brightness/contrast adjustment layer to brighten the wings of the left-most seagull. I have clicked the setting for just the layer below, and applied a layer mask that masks (black) everything except the wings on the bird (white patch on mask), so the head is not brightened.
Note that I chose to use an adjustment layer. I could have used the menu to make the same adjustment, but that would have adjusted all of the underlying layer (and just that layer), and done so destructively, so I could not go back later and adjust the filter settings.
Layer masks
Layer masks control which parts of a layer are visible and which are hidden (transparent). Here is an example. One might consider the brick wall behind the face to be a little boring. Let’s change it for something more exciting.
I found a landscape and pasted it in below the face layer. Now, I could have erased the brick wall parts, so the landscape would show through, but instead I have selected and masked the face layer. Note the mask. White where we want the layer to show, Black where we want transparency, allowing the landscape background to show through. OK the selection round the head was a bit dodgy, but you get the idea. And if I want to put in the effort, I can tweak the mask to better refine the edge. I can select the mask then use the paintbrush tool to add white where I want transparency or black where I want.
Below is another example. Here I have blended grandmother and granddaughter portraits for this demonstration. I’ve used a mask with a graduation between white and black over the middle of the faces to create a smooth blending rather than a hard like of demarcation. You can paint on a mask with grey, or use a brush with a low flow to make softly blended mask edges too, or make them using feathered selections.
Masks can be much more flexible than these simple examples. In future I will post on Luminosity masks and other masking techniques.
Tip: if you have a mask, Ctrl-Click on the mask thumbnail to make a selection that matches the mask.
Tip: if you have made a selection, clicking the add layer mask icon at the bottom of the layers panel will make a mask matching the current selection.
Tip: if you want to duplicate a mask onto another layer, Alt-drag the layer mask thumbnail and drop it over the other layer.
Layer Opacity
Sometimes you may want the effects of a layer to be toned down. For example, you may have, say, an adjustment layer that you have applied but the effect is too strong. You can reduce the opacity of that layer to reduce the adjustment effect.
Another example, perhaps you want a mist-like effect. Make a new empty layer. Make a soft large white paintbrush with a low flow. Paint on the new layer where you want the mist to appear. Adjust the opacity of the layer to let some of the background bleed through to give the effect you want. Here is a very quick and dirty addition of some “mist” to a night shot from Southbank that I did just to illustrate this. By reducing the layer opacity the city lights shine through the “mist”. Really I need to add a blur layer, masked by the mist density, to give the lights through the mist a more natural fuzziness … and so on. Something for you to experiment with.
Really I need to add a blur layer, masked by the mist density, to give the lights through the mist a more natural fuzziness … and so on. Something for you to experiment with. Ok, here is another quick and nasty, with a blurred layer masked by the mist density. Not perfect, but hopefully you get the picture.
Blending Mode
Photoshop and similar programs provide a diversity of layer Blending Modes. These can be used for many different uses. Here is an example. The image below was a little dark. By duplicating the layer, and changing the blend mode to Screen we have produced a much better tonal range. Have a play with blending modes on your own image to see how it affects the interaction between a layer and the underlying layer(s). I’ll make a Blending mode post later to explain in more detail how you might use them.
Layer Styles
The layer styles dialog (double click on the layer thumbnail image) provides many options. Of particular note are Blend mode, Opacity (both also available at the top of the layers panel) and the Blend If, which can control which bits of the image are transparent based on the current or underlying layer. In some cases this can replace or supplement making a mask. There are also Blending Options including Stroke, Glows etc.. There is too much for this section so I will make separate posts on these various Layer Style features.
Filters (aka adjustments) are the workhorses of Photoshop and other image processing software. They handle simple adjustments like exposure, contrast, colour balance, and more complex processes like sharpening, blurring, removing noise, dust and scratches, not to mention adding “artistic” effects such as the painterly transforms.
In Lightroom you have access to a range of filters/adjustments in the develop module. These are basically the same as in the Camera Raw filter (see below). These adjustments can be applied over the whole image, or you can use the selective tools to apply them as a linear or radial gradient, or using the brush tool to apply them in specific places.
In Photoshop, some filters are accessible in the Image > Adjustments menu. However these overwrite the pixels in the layer you are working on. In the interests of a non-destructive workflow it is better to apply the filters as adjustment layers. Using adjustments on Smart Layers is often a good idea if you want to tweak the settings in later edits.
Camera Raw filter
This filter brings the power of Adobe Camera Raw to photoshop layers. It gives all the image adjustment controls you get in Lightroom, including Basic, Curve, Detail, Color mixer, Split Toning, Optics, Effects, and Calibration. Rather than reading about it, find an image, and apply a camera raw filter. Look at the options on the menu; have a play with them all to see what they do.
If you use a Smart Object layer (see Layers), then the camera raw filter will be re-editable, making it easy to tweak the settings as your development of the image progresses. This is also true of other adjustment filters.
Adjustment Filters
Photoshop and similar applications provide a wealth of adjustment filters. These include basic exposure adjustments, colour adjustments and inversion. A screen grab of the basic adjustment filter menu of Photoshop is shown here (from the adjustment layer tool). Other applications have a similar range of functionality. Some have various filters that include AI based software which can work well for some images. These can adjust tonality and colour balance including conversion to monochrome.
In some cases there may be an AUTO setting which might make a suite of adjustments to various tone or colour controls to optimise the image based on rules set in the original programming. It’s no harm to try this out. You can always undo the change and revert to manual edits, or accept the auto adjustments as a starting point to tweak to suit your own aesthetics.
Sharpen and Blur Filters
Sharpening filters generally work by finding edges and enhancing contrast from one side to the other. This can be very effective if used carefully, but overdoing it usually produces an unnatural look, with stark contrasts and halos (see example below). Some of the sharpening filters are generic, others are optimised for different types of blurring, such as motion blur, or focus blur.
Though we often strive for pin-sharp images, blurring filters are also valuable tools. You might, for example, want to visually separate the subject from a busy background – blurring the background is a good way to achieve this.
Blur filters have a multitude of other uses. For some examples look HERE.
In addition, blur filters are often used to adjust local contrast (for example see HERE)
Photoshop has a gallery of filters that give painterly and other effects to images. You can experiment with these filters with your own images. There are many resources on the web. some tutorials
Stuff on brushes and custom brushes. Include discussion of what is allowable – user made content vs bought content for comps etc.
Brushes – the standard brushes
Brushes are a common feature in image editing software. However, they have hidden depths, and the full range of brush settings huge. I will provide only a brief introduction and leave the reader to follow up with further reading (list at bottom). Another caveat: simple round brushes aren’t contentious in use for masking, dodging, burning, erasing etc. However using brushes to paint on a photograph starts to transform the image into a work of graphic art. For competition use, images should be essentially made using your own photographic imagery. A small amount of drawing on an image may be permissible, say for fixing a defect. But how much can you do before it ceases to be photographic? As you will see below, brushes aren’t necessarily simple round shapes, but can include images – think for example of those images of a violin, with musical notes scattering across the sky from it. Are those notes based on photographs you have taken and made into a brush (OK) or are they drawn using graphic art tools (???) or are they someone else’s images made into a brush (probably not OK).
The commonest brush you will use is a round brush of variable size and hardness that you use in photo post-processing is to paint masks over layers. This is the standard brush in Photoshop, and also what you get as a brush tool in other applications, like Lightroom, Luminar, Topaz Studio etc.
The photoshop brushes panel (left) where you can select different brushes. On the right you can see a paintbrush where I am adjusting the size using the Alt-right-click – up/down-left-right shortcut to set size and hardness. Note the paintbrush options in the options bar.
If you have a pressure sensitive drawing tablet, you can adjust brush size dynamically using stylus pressure. Otherwise, in Photoshop, you can use the brushes panel, or right click on the image to bring up the brush dialog, or you can hold down Alt whilst click and hold the right mouse button. Then you can change the size by dragging left-right, and change the feathering by dragging up/down. In Lightroom you can quickly adjust size and feather using the scroll wheel or shift-scroll wheel.
Other brush options include Opacity, flow and smoothing. Opacity limits the density of the stroke. If you have set colour to black and opacity 50% (with 100% flow) you will get a mid-grey brush stroke. Flow controls how fast the colour flows from the brush to the image. If you set a low flow, each stroke will add a small amount and by making multiple brush strokes you can build up density in a very controlled way.
Other Standard Brushes
Besides the simple round brushes, Photoshop comes with some brushes that to some extent mimic the effects you might get with different sorts of paintbrushes, or using different media to paint with. These are listed on the brushes panel, and come with some presets, though you can customise the brush behaviour using the brush settings panel, where you also can find a selection of other brush tip shapes.
The Brush settings modify the behaviour of the brush and are extensive. They cover dynamics like variation in the size of the brush as you move it. The angle of the brush can vary. If the brush is not round, the angle can dramatically affect how the brush operates – think about what you get with a calligraphic pen. Some drawing tablets can sense the angle you hold the stylus and pass this to Photoshop. Scattering affects the level of randomness about where the brush tip is stamped onto the image as you move the brush. and so on… there are lots of options, and it is best to play and see what these controls do, particularly as their effects vary depending on the pattern of the brush tip.
Custom Brushes
You aren’t limited by the preset brushes in Photoshop. You can define your own. Here is an example.
… to be continued when I get time and inspiration…
is selected), Paint Bucket tool 
, Brush tool 
, Pencil tool 
, Fill command, and Stroke command. You must be in a layer with Lock Transparency deselected to use this mode.
at the bottom of the layers panel, the selection will be converted to a mask, and the selection will be deselected. You can refine the mask made this way by painting over it (see below).
