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stuff from Tim
Here is a link to a video which I thought was pretty good for the starburst effect:
I tried this out and I did not have as much success as was evident in the video – looks like the brushes are slightly different in my version of Elements (15).
Another video which goes further and shows a simple way to create your own starburst brush is here:
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Colour vision and the human colour perception
metamerism
basic concepts of colour capabilities of devices,
why use a colour management workflow?
gamut
colour space
mapping between RGB, CMYK, LAB. Color spaces sRGB vs AdobeRGB
RAW –> demosaicing/interpolation.
ICC profiles – cameras –> monitors –> printers / web / digital display
Proofing views and out of gamut warnings
Colour calibration software and hardware
Colour is complex, and you can find hundreds of books on the topic and a search for “photography colour management” on a popular search engine found 121 million hits today. My notes here will be just a brief introduction. I will post more later in the Advanced Techniques section.
Think, for a moment, about the qualities of light. in the hour after sunrise or before sunset, sunlight is much warmer – yellows, oranges and gold, than in the middle of the day. The light from your old tungsten light globes (yellowish) is very different from your fluorescent tubes (greenish) or your Xenon strobe flash gun (probably “daylight” balanced). In photography we use a scale called Colour Temperature which approximates the colour of light from a heated filament at different temperatures. Think of the colours as you heat metal in a furnace – dull red at first, warming to white hot. Colour temperature in photography ranges along a yellow (cool, low temperature) to blue axis, and usually there is a tint control that adjusts colour on a magenta to green axis. Together these give a great deal of fine control.
In your camera you will probably note that there is a “white balance” setting, which might be set at auto (camera will decide) or presets like “daylight”, “shade”, “tungsten” and so on. These controls do not affect what the sensor collects, but if you are taking photos in JPEG then they affect how the colours are translated from the sensor to the JPEG file. If you take RAW files, the colour balance setting is less important. All the sensor data is present in the file, and the colour balance setting just determines how these are translated into the displayed image. You can freely adjust the colour temperature (and tint) in your Raw processing software. If you took a photo in the middle of the day using, say, tungsten light setting, the image will probably look blue. Click the colour temperature setting in your software to “daylight” and the image will look more natural. The image below was taken with tungsten light. With tungsten colour balance (colour temperature 2850 Kelvin- the temperature of the filament in a tungsten lamp), the pen barrel and background look white/grey. With Daylight setting (5500 K, about the temperature of the Sun’s surface) we have a distinct colour cast. Note the eyedropper tool. Click on this and click it on the image where there is something that should be a neutral grey colour, and the software will automatically adjust the Temp and Tint over the whole image to make that area neutral grey. This is a great way to make a start on colour balance, especially where you have difficult light (assuming the image has some neutral grey objects to click on). There is also a dropdown selection of fixed presets or you can tweak the Temp and Tint sliders.
No matter what software you use, you will find colour controls similar to those in Photoshop and Lightroom. Below I will explain some of the features in the Adobe programs, but if you use something else, have a look because the controls on your software probably work in a similar way. If not, consult your software vendor’s website or the internet for instructions specific for your software.
Among the Lightroom Develop controls you will also find saturation and vibrance sliders. As the name suggests dragging the saturation slider to the left will reduce the colour saturation. At the far left you are left with a monochrome image. A slight reduction in saturation suits some images. Increasing the saturation might be of value where an image is looking very flat and dull, but take care. Saturation increases the intensity of all the colours in the image. Raise it too much and you can get clipping, where the colours are blown out. Vibrance is a bit more selective. It pushes the saturation in the areas of the image where the colours are more muted, but leaves the already highly saturated parts alone. Have a play with them on your own images to see how they affect the appearance.
The next tool to discuss in Lightroom is the HSL (Hue/Saturation/Luminance) control. The colour panel gives you hue, saturation and luminance sliders for Red, Orange, Yellow, Green … which allow you to tweak these properties in the image over the corresponding colour bands. Or, you can click the small direct adjustment tool (circle at the top left) then drag over a colour on the image to tweak the hue, saturation or luminance of just that colour range. Very handy.
Split toning allows you to change hue and saturation separately for the highlights and shadows. Consider a scene illuminated by a setting sun. The highlight areas will have an orange glow, whilst the shadows will be bluish as their light comes from the blue sky above. You can tweak, say, the shadow tones to make them less blue without altering the highlight toning. Or maybe you want to create a more golden-hour look on a midday photo. Adjust the highlight colours towards orange / yellow; maybe tweak shadows towards blue. Have a play to see what you can do.
The Tone curve control also allows you to make separate tone curves for Red, Green and Blue channels which also alters colour balance. However this approach can be difficult to get right, so I’d recommend sticking to the other controls mentioned before.
Local colour adjustments are also available using the brush or gradient tools to apply the colour tweaks to specific areas of the image.
In most image editing applications there are several adjustments for colour; I have listed the main controls here from the Adobe website :
Adjust Levels Auto Quickly corrects the color balance in an image. Although its name implies an automatic adjustment, you can fine-tune how the Auto Color command behaves. See Remove a color cast using Auto Color.
Levels command Adjusts color balance by setting the pixel distribution for individual color channels. See Adjust color using Levels.
Curves command Provides up to 14 control points for highlight, midtone, and shadow adjustments for individual channels. See Curves overview.
Exposure command Adjusts tonality by performing calculations in a linear color space. Exposure is primarily for use in HDR images. See Adjust Exposure for HDR images.
Vibrance command Adjusts color saturation so clipping is minimized. See Adjust color saturation using Vibrance.
Photo Filter command Makes color adjustments by simulating the effects of using a Kodak Wratten or Fuji filter in front of a camera lens.
Color Balance command Changes the overall mixture of colors in an image. See Apply the Color Balance adjustment.
Hue/Saturation command Adjusts the hue, saturation, and lightness values of the entire image or of individual color components. See Adjust hue and saturation.
Match Color command Matches the color: from one photo to another photo, from one layer to another layer, and from a selection in an image to another selection in the same image or a different image. This command also adjusts the luminance and color range and neutralizes color casts in an image. See Match the color in different images.
Replace Color command Replaces specified colors in an image with new color values. See Replace the color of objects in an image.
Selective Color command Adjusts the amount of process colors in individual color components. See Make selective color adjustments.
Channel Mixer command Modifies a color channel and makes color adjustments not easily done with other color adjustment tools. See Mix color channels.
GIMP is a cross-platform image editor available for GNU/Linux, OS X, Windows and more operating systems. It is free software. GIMP provides sophisticated image editing tools similar to those in Photoshop. There is a vast array of 3rd party plugins that can extend the functionality of GIMP.
GIMP is extensively documented online, including a range of tutorials ranging from then basics of installing and first use, through to sophisticated techniques like luminosity masks. The built in help module is extensive.
The following list (from the Help File) is a short overview of some of the features and capabilities which GIMP offers you:
Gimp handles RAW files through use of a plugin like Darktable or UFRaw. Once these are installed, Raw file handling is straightforward.
Gimp supports layers and masks, sophisticated selection tools (some built in, some obtainable as plugins), and flexible file output options. It lacks filter layers, unfortunately, but you can always duplicate a layer/layer group and apply the filter to that layer. It’s not quite as flexible as PSs filter layers, but it gets the job done.
It is not as fast, and not as refined as Photoshop, but for the price ($0 for a perpetual licence including lifetime updates) it is superb. I use it sometimes for features that Photoshop lacks.
The user interface is a little different to that of Photoshop, but it is very customisable, so you can set up keyboard shortcuts and other tweaks that give you a more PS-like look-and-feel.
The current offering from Skylum (as at Jan 2023) is Luminar Neo. https://skylum.com/luminar
It offers extensive AI based editing functionality. It has powerful editing filters, layers (so you can do things like replace skies, and make composit images, apply texture overlays etc). It has denoise filters, upscaling and a host of other features. As these change regularly, I suggest you do a web search for recent reviews (don’t use older reviews, they can be misleading, but here is one that is current as I write this (jan 2023) https://expertphotography.com/luminar-neo-review/).
The user interface is straight forward and logical, and includes tabs for file management (catalog) and editing. It supports editing presets that can be useful to quickly apply a suite of editing steps to a photo (or a batch of photos).
Among the touted feature list (some of these are in the extensions pack at extra cost):
Skylum allow you to download a 30-day trial, so you can see if it suits your needs before purchase.
The ultimate aim of post processing is to produce photographic art, be it a relatively straight forward edit of light and shadow, or more complex manipulations including compositing. This section will cover some Artistic aspects of photography from inspiration to the final product.
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Your images are composed of pixels, each representing a spot of colour. Typically your camera will produce images more than 2000 pixels (px) high and more than 3000 px wide. The more pixels, the larger the storage needed for the files and the more bandwidth needed to send them electronically. If you want to use one of your images on the web, or perhaps submit to WCC for one of our monthly competitions or an outing gallery, you will need to produce a reduced size copy to a smaller specified size.
Tip: Always make a reduced size image as a copy. Don’t overwrite your original file.
In Photoshop, resizing images is easy. First save a copy of the full size image (eg MyBeautifulLandscape-2048px.jpg) using the File > Save as menu. Now you are ready to resize. Open the Image > Image Size menu to show the Image Size dialog.
You will note that there are boxes for Width and Height. Check that the units to the right are set to Pixels. Check that the chain symbol linking width and height is set. This ensures the width and height will change in concert so there is no vertical or horizontal stretching in the result. Check the Resample check box is set. For WCC competitions images need to be at most 1920 px wide and at most 1080 px high. So, in the dialog enter 1920 Pixels in the width box. As you enter numbers, the height is automatically adjusted to match the image aspect ratio. Is the height 1080 or less? if you are ready to move on. However, with my image this reset the height to 1280 pixels, which is greater than 1080, so we need to make the height less. Change the height setting to 1080 Pixels and click in the width box. Width is 1620, less than 1920, so this is acceptable. Try not to use sizes where both the width and the height are less than the maximum allowed. If you do, your image will look small when shown at competition night, and the judge may find it hard to assess a smaller image.
If the image is for electronic display the resolution setting (here 240 Pixels/inch) is not important – it might make a difference if you are pasting into a wordprocessing document or presentation software. Best idea is to set it at one of the standards, 240 or 300 pixels/inch.
Next to the resample checkbox is a control to set the method for resampling. Usually you would use the Automatic setting.
Once you have configured the dialog simply press OK. The image will appear to shrink on screen (Image Size does not change the zoom setting. Press Ctrl-0 to expand the image to fill the window, or Ctrl-1 to zoom it to 1:1.
Save the image (as JPEG for WCC competitions), and you are done.
In Lightroom you use the Export module to export images (see below). Set the required size in Image Sizing, configure whatever else is needed, and click OK.
You might want to resize the canvas without changing the pixels on the image. For example you might want to add extra sky above an existing image. In Photoshop you use the Image >>Canvas Size menu. This shows the current size in pixels. To add, say, more space at the top, the Relative checkbos determines if the pixels you add are added to the existing pixels, of if the pixels you set are the final canvas size. Set the Anchor at the bottom (so the extra space is at the top), and enter a new canvas size, with the current width and some extra pixels height (see right). Choose the extension colour – what colour the newly added pixels will be, and click OK.
You can use tools like Content Aware Fill, or careful clone stamp use, to fill in the new area in your image.
Below some Club Competition specific resizing instructions
from the WCC website
If this is all too much, I made a web form to resize and rename images for WCC competitions. http://austvic.com/wcc/
You might want to restrict an edit to a particular area of your image. You might want to move an object within your image. You might want to, for example, select a bird (or three) from one image, and place them on a different image.
Selection tools have options like feathering.
If you need to make precise selections, I suggest zooming in to greater than 1:1 (100%) so you can most clearly see the edges you might want to select. You may need to do a bit of scrolling to get around the whole image, but your selections will be more accurate and so it is worth the extra time. Selection tools come with options like feathering, and in general you can make a partial selection, change tools or tool options, and resume, adding to the selection, or perhaps subtracting from the selection. You might want to save a selection as you go for complex (time consuming) selections.
Photoshop has multiple selection tools and multiple options for the tools. Rather than me spending hours reinventing wheels, check out Adobe’s Selection tools HERE. Note that there are some very sophisticated automatic selection tools – notably select subject and select focus area on the Select menu that usually give you a good starting point (they often need a bit of refining, but they can sale a lot of time). The Select and Mask tool is also very powerful. Read more about these quick selection tools via the Adobe training website HERE.
Note that once you have made a selection you can:
Some notes on applications other than Photoshop
Layers are a workhorse of post processing and are worth a little effort. They will save you much stress and wasted time as part of a non-destructive workflow. I give a basic introduction to layers and masks below. I go into more detail on these pages: layers, masks, and there are links at the bottom of this and my other pages to further tutorials.
Think of layers like a set of acetate sheets on top of your base (background) image. These layers can adjust the image (exposure, contrast, curves etc), or overlay new image components Below is an example. The background layer contains the milky way. On top of that I have some adjustment layers to adjust the tonal range and to reduce image noise. On top of that I have added a spaceman (actually a photo of a sculpture outside the space museum in Leicester). Further layers contain the spanners, nuts and bolts that I have strewn across the starfield. Each layer adds a new component to build up the final composition.
I could have done all these edits on the one background layer, selecting and pasting the spaceman directly onto the starfield layer, but if later in my processing I decided I wanted to move the spaceman (or a spanner) I would have to start again from scratch since I would have replaced part of the starfield background with the newly added objects. Since the different image parts are in layers I just need to move the image in the relevant layer. The starfield layer is intact so when I move an overlying layer, the starfield under the spaceman reappears as I move them. Likewise I can adjust exposure, curves etc on each layer individually to ensure all parts match up in lighting and tonality.
You might notice that for some layers, to the right of the layer thumbnail is another thumbnail filled with black and white shapes. These represent layer masks. A mask, as the name suggests, hides things. About 3 layers down in the example, you see a layer labelled Black Spaceman, with a layer mask. The mask is masking (hiding) some bushes and buildings and the pedestal that were parts of the original image of the statue that I don’t want to appear in my composite image. Not only can masks blank out part of an image layer, they can be used to mask adjustments. For example with a landscape photo, you might want to darken the sky. You could apply an adjustment to darken the sky, but this will also darken the ground. However if you apply a mask to the layer you can limit the darkening just to the sky. And if you are clever you might use a gradient from black to white in your mask. Black masks (turns off) the adjustment, white gives the full adjustment, and levels of grey give partial effect of the adjustment depending on the greyness.
Consider the landscape below. To me the sky looks a little washed out.
So let’s apply a curves layer to tweak the sky. Now the sky looks better, but the foreground is now too dark.
So, click on the adjustment layer mask and draw a black to white gradient going up a little from the horizon. I also painted black on the mask in the area over the hills above the horizon so they weren’t darkened. Compare this image with the image appearance we started with. Hopefully you will agree that it is improved. Still not happy – just tweak the curves further, or add a new adjustment layer to add to the adjustments. Want to compare before and after? click on the eyeball to the left of the layer to turn the layer off and see the image without that layer. Click the eyeball again to turn the layer on again.
You can see the mask on the curves adjustment layer thumbnail, but this doesn’t show the mask very clearly. Here is what the mask looks at full frame like in quick mask mode (Q) with the quick mask options set for opaque black to really highlight the boundaries of the mask. Normally the quick mask gives a red mask with 50% transparency so you can see the image underneath, but in this example I wanted to show the mask more clearly.
Below the same image with the normal quick mask settings. You can see all the image through the quick mask, but the details at the edges (eg the masking of the hills on the horizon) are not so clear,
Hopefully I have convinced you that layers and masks are an essential part of your processing workflow. Check out the Resources section below for more detail on how to use them.
Note: in PS layers called Background have special properties. PS limits some edits on them to preserve your original image. You can duplicate the image (Ctrl-J) or menu Layer > Duplicate layer, to make a normal layer with the image copied in, or double click on the background layer name and rename it so it is no longer limited as the background layer (an image does not need a background layer).
If you want to come back to your image later and change the exposure, you can adjust the settings on that exposure layer. You aren’t changing the original image so you can come back as often as you like and tweak things with no accumulating image degradation. Want to go back to the original image? turn off or delete the adjustment layers. These sorts of edits are called non-destructive edits.
If you aren’t using PS, you may still be using layers and masks. When editing your images in Lightroom, layers are used, but LR simplifies life for you by hiding the layers. When you apply a global change, say in exposure, LR creates an invisible (to you) layer with the exposure adjustment over the top of the original image layer. The local edit tools (linear gradient, radial gradient, brush tool) you are effectively creating adjustment layers with masks. If you want to see the mask, click the check box Show selected mask overlay underneath the image, and a translucent red mask will show you where the effect is active.
Luminar, Affinity Photo, Topaz Photo Studio all (I think) allow you to add adjustments on layers. they also allow you to add image layers for a texture overlay, replace backgrounds or to add new elements to the image. They work in similar ways to what I have described above, but consult the application documentation to discover the nitty-gritty for those applications. Lightroom and DxO Photo lab don’t have layers, as such, but allows detailed local adjustments to be applied – effectively adjustment layers with masks; however the equivalent of image layers are not available in these applications (at present) .
With Levels and Curves you can fine tune the tonal range and even colours in your images.
In Photoshop the Layers dialog has many features. The main ones are labelled below.
Try out the AUTO settings – it will try to balance the photo to a reasonably distributed histogram. Sometimes it works well, at least as a way to get started. If you don’t like the result, you can undo it (Ctrl-Z or Edit>>Undo or click back in the History panel). Click the black, mid or white eyedropper and then click on your image in a black/mid/white area. The channels will be balanced to produce pure black/mid grey/pure white for the tones selected. This can be a great way to clear a colour cast (eg a bluish tone in shadows).
Play with the adjustment sliders to see what they do. You can set the output range to limit the maximum white or black.
If you want, choose one of the individual colour channels rather than the overall RGB. Adjusting levels in a single channel will alter the colour balance and can be a good approach to dealing with colour casts (also look at split toning).
Curves adjustments are similar to Layers, but this allows more nuanced adjustments. On the histogram is a black 45 degree line which represents no change. If you click on the line to add a control point and drag the line upwards or downwards, you will lighten or darken the relevant tones. By adding multiple control points you can selectively alter some tones but not others. Click on the on image adjustment tool, and you can drag on an image area that you want to adjust (drag up to lighten, down to darken). You can remove control points by dragging them off the dialog.
Choose an individual colour channel rather than RGB to selectively adjust a single chanel at a time. This can be very useful to remove (or add) a colour cast, say to shadows.
Levels and Curves adjustment layers can be masked to limit the areas on the image that are affected by the adjustment.
In the image left you can see some of the layers as I edit an orchid photo. I have a curves layer that is masked so it adjusts just the background and a brightness layer that is masked to adjust just one of the petals that was too dark. See the section on Layers and Masks for more info.
By default levels or curves adjustment layers works on the combined output of all the layers below it. But at the bottom is a control to limit the effect of the adjustment just to the layer immediately below.
