appletalker scrapbook: extreme contrast in photoshop

here's a handy technique for really giving your images some hyper contrast in photoshop.

let's take an image which looks a bit wishy washy and see what we can do to make it a bit more punchy.

here's one i prepared earlier:

traditionally you would up the contrast of an image like this by using photoshop's brightness/contrast slider, either by applying image > adjustments > brightness/contrast directly to the image or, if you're a wee bit smarter and prefer to work non-destructively, by using a brightness/contrast adjustment layer.

applying a brightness/contrast adjustment layer:

let's throw the contrast up full:

layers panel, showing the image with the brightness/contrast adjustment layer applied:

and here you have the final result - our wishy-washy image with the contrast shoved all the way up to 100%:

it's a lot better, but it's not 'hyper-mega-super-eleventy billion 111!!!-contrasty©'.

we could increase the contrast by applying another adjustment layer... and another... and another... but that's a time-consuming way to go about it and it also looks absolutely shite, as the image will very quickly start to almost posterise as you layer on additional contrast layers.

there is a better way and, weird as it may seem, it involves using that old favourite of anyone who's ever brought a scanned image into photoshop and had to sharpen it up; namely the unsharp mask filter.

first of all we need to select our image layer and choose filter > convert for smart filters [smart filters are the filter equivalent of adjustment layers, in that they allow us to piss about with filters in a non-destructive way. the original image remains untouched and the effects of any smart filters we apply can be increased, lessened or removed altogether].

convert the layer for smart filters:

next you need to apply filter > sharpen > unsharp mask to your image:

usually, when using the unsharp mask filter for it's 'regular day job' you'd start with the radius down quite low and the amount up around 50% and start twiddling from there. when using unsharp mask as a 'hyper-mega-super-eleventy billion 111!!!-contrasty©' filter, you start off the other way round.

turn the amount right down to 1% and whack the radius up to somewhere between 80 and 100 pixels:

now start edging the amount slider upwards. as you do so you'll notice that the contrast of your image starts to increase really dramatically. you'll also notice that you've got a helluva lot more contrast to play with as, unlike the traditional contrast slider, which only goes up to 100% - in true spinal tap fashion, the amount slider of the unsharp mask filter goes up to 500%. so you can add far more contrast this way than you can using the actual contrast controls in photoshop.

in the image below, i've knocked the amount up to 134%. that's probably a bit much for this image, as it's starting to bleach out in places, but it gives you an indication of what this technique can do. theoretically i've still got another 366% to play with [although in practice the image will break up before you get anywhere near that level].

amount turned up to 134%:

i eventually went for somewhere about 109%:

as you can see from the comparison below, the unsharp mask filter with the amount slider barely off the starting blocks gives far superior contrast to the brightness/contrast adjustment layer, running at full speed. it's an interesting technique and well worth having a tinker with, if you really want to go for some extreme contrast.

unsharp mask technique [LEFT] - traditional brightness/contrast adjustment layer [RIGHT]: