Curves tut

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Turning lead into gold - a curves tutorial

In this tutorial I intend to talk a lot about curves and what they are capable of

I am a huge fan of curves myself, so much so that I never use brightness/contrast anymore to bring out drab areas in photographs or sigs.

Contrast is one of the curves editor’s biggest strengths and the easiest to achieve I think, instead of using the brightness/contrast or levels to give contrast to anything we can now use curves. Curves give a lot more control over the areas you want contrasting/brightening/darkening etc...

Ok, so how to find the curves editor. There is many ways to do this. If you wanted it just to apply to one layer in Photoshop you can bring it up by pressing ctrl+M on he keyboard or going to image>adjustments>curves, if however you wanted to apply this to all of the layers in your stack (useful for sigs) then you would create a new adjustment layer. Either by clicking the half white/half black button at the bottom of the layer stack and choosing curves, or by going through the menu layer>new adjustment layer>curves

The curves interface;



There is your basic curves interface, to add points you have to click on the line, and then you can just move them around to adjust the shape of the curve

You can see on the curves box that it acts on 2 axes; this is read just like any graph you could encounter, first read off the horizontal (bottom) and then the vertical (side)

I will be using this simple medium grey box to show you how Photoshop interprets the curve that you draw



Now there is our simple grey box, colour #808080

Bring up the curves dialogue now (ctrl+m) and adjust the curve to look like this below (ignore the arrows)



You see how it has become much lighter, whats happening here is that Photoshop has looked at the grey along the bottom axis and said right, change it to what is along the side axis (the lighter grey in this case). If you were to change it to be a lower value, it would then darken the grey

This is very useful in photographs or sigs that have a lot of washed out grey that doesn’t look very good and you want to get rid of, giving it a much more crisp and contrasted look

have a play around with various images and mess with different shaped curves to see how it interacts with the image and what an improvement it can make if used right.

Turning lead into gold

Curves isnt just limited however to acting on all channels (RGB) we can affect different colour channels also.

for this part of the tutorial I will be using this image


source http://www.tate.org.uk

we will be turning this lead statue into a very attractive gold one

first thing to do is open the image in Photoshop, then create a new curves adjustment layer (see earlier). The reason I am using an adjustment layer and not just editing the image directly is that I want to add a layer mask because we only want to affect the statue, not the background behind it

here is the layer mask, if you dont want to paint it yourself;



your layer palette should be looking like this now;




see next post for part 2 (image limit)

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with that done slightly adjust the RGB curve to look like this



that'll just darken the image to give a much better look to it

now, clicking the channel dropdown at the top of the box, choose the red channel first (or press crtl+1)

change the curve to look like this:



now, change the channel to the green one and adjust the curve to look like this:



and finally adjust the blue channel to look like this:



and there you have it, just click ok and you have successfully changed lead into gold, something alchemists have failed at for centuries :P)



another sig example



hope you learned something from this tutorial into the way curves work and how they can drastically improve you work

If you have any questions or comments, please feel free to ask by posting here, pm or msn

[Soulless]

wow that lead to gold very nice, ive just learnt curves before this but that lead to gold is very nice

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Originally posted by Soulless@Jun 24 2005, 03:43 PM
wow that lead to gold very nice, ive just learnt curves before this but that lead to gold is very nice

[snapback]48083[/snapback]

thanks

[FendeR`]

When I saw the title, I didn't think you'd do it literally. :P But that's pretty nice, but I think basically as far as trying to improve your sigs, you just have to play around with it (I don't think you can really teach how to do it). That's really cool how you made it gold though, nice insight.

[imported_Jack]

I was just looking over your tutorial. You know what your doing, but I noticed that it might save you some time if you just select the statue, and then colorize it. I have a small example here and aside from a few subtle differences, I got pretty much the same effect. After selecting, it took me about 10 seconds using hue/saturation to get a similar color. Your shadows on the left of the statue has a hint of green in it though. Thats the main difference. But i understand what you were trying to show people

[J.G. Artist]

ilike it i dont no when i would ever use this but i like it