Match tone and colour in Photoshop
First published in Computer Arts and Creative Bloq, and in updated form here.
The New York pack contains many reverse-engineered image processes. But how do you reverse-engineer another photographer, retoucher or even painter’s work for yourself, and why might this be useful?
Well as a professional retoucher or photographer, you tend to find people commissioning you for work already know the kind of result they’re after. In fact so fixed are most marketing departments on what they want, your work will be judged almost entirely by how closely it resembles the images on the mood board. Hence: your originality may get you fans, but your ability to shamelessly copy will likely get you more work.
Not to mention you can learn a lot about contemporary image processing trends and techniques in the process.
This is a simple, multi-layered workflow for matching one image to another. Many of the New York pack processes go a little deeper, and involved reverse-engineering selective or area-based effects too. More on them in future articles.
So, the first thing you’ll need to do is load your unprocessed image and the image you’re trying to match it to into Photoshop (any version back to 3), then set up a workspace where you can compare them side by side on separate layers.
It doesn’t matter if we have to resize the images to make them fit, because we’re really just finding the settings that will work. Curves layers are particularly powerful for controlling tone and colour. In fact, there’s very little you can’t do with them.
The first thing you need to do is set up your workspace. Arrange both images side by side on separate layers, with the unprocessed image on the bottom. Create two Curves layers and a Hue/Saturation layer above the unprocessed image, but below the image you’re analysing. (The New York pack contains a quick set-up preset so you can start matching one image to another with the click of a button.)
Now create a Solid Color adjustment layer, set it to 50% grey (RGB: 128, 128, 128) and put it on top of all your other layers, along with a Selective Color layer.
To match the tonality of the images, make both images appear black and white. To do this, change the Solid Color layer’s blending mode to Color. Then select the lowest Curves layer and change its blending mode to Luminosity.
Use your Marquee tool and the Histogram panel to match your black and white points in the Curves layer first. Now experiment with subjectively matching contrast and tonality with a 1- or 2-point curve.
To analyse the colour, go to your Solid Color layer and change its blending mode to Luminosity. Now you can see your images represented as coloured splodges.
Select your second Curves layer – keeping its blending mode set to Normal – and using the Red, Green and Blue curves, we can attempt to match the colours we find around our highlights and shadows. Set black and white points first.
Now we can move on to matching colour saturation levels. Go to your Selective Color layer – ensure it’s set to Absolute mode, rather than Relative – then cycle through the colours in the pull-down menu: Reds, Yellows, Greens, Cyans, Blues, Magentas, Yellows and turn the Black slider down to −100% on each of them. Then cycle through the neutral colours: Whites, Greys and Blacks, and turn the Black slider up to +100%. This is a useful preset to have which could call a ‘saturation mask’.
This should leave you with strange-looking black-and white images, with the white representing full saturation, and the black full desaturation. Now go back down to your Hue/Saturation layer (I like to set its blending mode to Color) and simply adjust the Saturation level until you get the two images roughly matching.
You can then turn the Saturation Map’s visibility off and repeat the whole process if you need to. Again, this won’t work with everything, but it’s a core technique in how we match tones and colours.