Mountain Photography Adobe Photoshop Tutorials

This is a tutorial on contrast masking with Adobe photoshop. It is probably more suited to the advanced user of photoshop, but you may be able to pick up some information no matter what level of user you are. Masks are a good way of overcoming the limitations of tonal corrections using the standard photoshop tools like levels and curves. The levels allows you to increase the tonal range of a file and then change the midtone values, which works well in some cases but is very limited because you can only really shift the midpoint. Curves allows you to change the tonal values of specific pixels in the file but if you create more than one point on the RGB composite curve and pull you start to create very damaging colour shifts. So curves works well for fine tuning but is not great for dramatic tonal shifts in specific areas. This is where masks come in handy. I will go through this exercise from the raw scan through basic image correction, through to masks and then on to the channel mixer and sharpening.

Part One: Basic advanced image correction , levels and curves.

scan

This is the basic scan. I never use any correction in the scanning software so my images usually look a bit rough. So first thing I do is create an levels adjustment layer and manually adjust each channels highlight and shadow. The red and green highlight are a bit of a guess, but that will get me going without clipping all the highlight pixels in those channels.

levels

levels_robson

Next we set a grey target for the curves with the colour sampler tool, in this case I will try one of the rocks on the beach. Probably a good guess.

Next I create a curves adjustment layer and set my grey target between my high and low values on the channels. In this case 98 plus 105 divided by two is about 101. That makes sense because the file looks like it already has good grey balance.

Then I use the composite RGB curves and increase the tonal values of all the layers to generally brighten the file. I could have done that in levels, but it does not really matter.

curves_rgb

The file is starting to look pretty good but we can do a lot more with masks if we want.

Part Two: Masks

What this will allow us to do is now deal with specific parts of the file that still have tonal problems one way or another. The first area I would like to improve is the right corner where the trees are. They look a bit dull compared to the slide so this mask will help me with that. I duplicate the original layer and set the blending mode to screen. Then add a layer mask and paint out the areas with black that I do not want the mask to effect. Keep in mind you can always back off the opacity of the layer if the effect is to much.

trees

That works with the trees but now the next problem is the sky, it is a bit under saturated so I do exactly the same thing. Create a duplicate of the background but this time set the blending to multiply. Notice the opacity of the layer in this case is only set to 20% and I also used a black to white gradient to feather the effect as opposed to painting areas with a brush.

sky_layers

sky

OK, the file looks pretty good now with the exception of two areas. Firstly, the shadows are totally blocked out on the left. The result of this being when I go to print out the file it shows up as a black blob with no details at all. Remember if you have even a bit of problem seeing details on the screen in either the shadow or highlight areas there is no way you are going to see anything on the print. Secondly, the top part of the mountain with the snow is now totally washed out. To address the shadow problem I look at my channels individually and see which one has the most detail, for my scanner it is usually blue so I make a note of that for later. I make sure my background layer is active and go to the select menu and activate the colour range command. From the drop down menu I choose shadows and it creates a selection of all of my shadow pixels. With this active I create a channel mixer adjustment layer and that applies the selection to the mask automatically. The screen capture below has the mask active (Alt/Option click on the mask thumbnail) in order to show what is effected by the layer.

colour range

mixer

I mix the channel information in the channel mixer by mixing the blue channel information into the red and the green, remember when doing this the values add up to 100% per channel.( I then created another levels adjustment layer and clipped(grouped) it with the channel mixer I pushed up the midtone slider to increase the effect so it was easier to see on this tutorial, but you probably would not have to go that.)

channel_levels

The final tonal problem with the snow I address by again going to the background layer and making a selection of the burnt out snow with the magic wand. I then feather the selection, how much you feather would depend on the resolution of the file but you are looking for a gradual effect. With the selection active press Ctrl/Command + "J" this will copy those pixels to a new layer. I took that to the top of the layer stack and placed another levels adjustment on top of that I played with the levels to make the snow darker and then clipped(grouped) the snow layer with the levels. The only final small problem was that when I made the snow darker it was a bit oversaturated and shifted to blue. I corrected this with a hue/saturation adjustment layer and again grouped it with the snow and the levels to isolate the effect.

levels_sat

snow

layers_masks

Part Three: Final Sharpening.

The last step I would perform is a final sharpening using a duplicate of the background with the high pass filter run on it. Set the blending to overlay and adjust it according to what you need. I set my filter to 10 pixels and as a result had to lower the opacity a lot.

layers_final highpass_filter

final

Done..ready to print!

This is the original for a final comparison.

Anthony