Gradient Map in CS4

[Kennet...@adobeforums.com]

I've just installed Photoshop CS4 but the Gradient Map tool is not working for me as in CS3.
I want to change colors of black lines on a clear background ( in a CMYK document) to 100% cyan.
I have done this many times in CS3 using the Gradient Map and setting both beginning and end points to 100% C and other colors to 0%. However, now it comes out to 69%C15%M0%Y0%K.
I have not changed any defaults in the PhotoShop program. Solutions?

[PECour...@adobeforums.com]

Is your document really in CYMK? Is the black black? Normal color settings?

[christoph_pf...@adobeforums.com]

No answer to the actual question, but why not use the Channel Mixer in this case?

[Kennet...@adobeforums.com]

Thanks for your reply.
Yes, the doc is definitely CMYK. In fact I can open the same doc in CS3 and it will work fine and then, without saving, open in CS4 and I cannot get the GradientMap to make 100%K or the 100%C (depending on which gradient I selected in the GradientEditor, 100%Cto100%C or 100%Kto100%K). I have done this many hundred of times without difficulty. I have not manipulated the color settings. They are set to whatever is the default after the CS4 was installed. I just tried this on my laptop and this was the first document opened after I had installed CS4 and the same result. I am not familiar with color settings so I haven't touched them.

[PECour...@adobeforums.com]

Just tried with gradient map, in CS4 and got readings close to yours... Even with 100 in every colour. Don't know how it was supposed to work in CS3.

Christoph has a good point

[Kennet...@adobeforums.com]

I would like to work with file having elements ( probably scanned image lines impure black [75%C75%M75%Y90%K])on two different layers and I delete the white backgrounds of the layers. On one layer I want 100%K and another layer 100%C.
What settings would I use in ChannelMixer to attain 100%K on one layer and what settings would I used to get 100%C on a different layer?
Thanks

[christoph_pf...@adobeforums.com]

I can’t reproduce the problematic behaviour.

The pure black I would personally prefer to attain using a Hue/Saturation-Adjustment Layer set to Colorize with 0% Saturation (and a Curves-Layer to get to a 100% if necessary) and over that place a Channel Mixer-Adjustment Layer with Cyan set to 0%CMY/100% Black and all the others to zero everything.

[christoph_pf...@adobeforums.com]

If You want to delete the white backgrounds and avoid possible fringe-pixels-problems I would recommend to make a layer-mask of the black channel and apply it to a Solid Color-Layer of 0/0/0/100 actually.

[Kennet...@adobeforums.com]

open the scanned file into Photoshop
1. change the do type to CMYK
2. duplicate the layer, change the background to white
3. Apply Threshold to Layer 1 , adjust the slider to desired density, thickness of line. use Wand tool the select and delete white background.
4. Apply GradientMap (color chip 100%Kto100%K) the get Black (100%K) lines.
5. Then I lasso-select the lines I want to be Cyan and com-J to put them on a new layer and I refine the lines with erase-pencil.
6. Apply GradientMap , this time with color chip 100%Cto100%C to this new layer.
It takes much longer to explain than to do it. Except for refining (which depends on the complexity of drawing) it only takes seconds.

The GradientMap should apply a given color(s) to the lines but some setting is different in CS4 on installation and I would like to find how to set it correctly so that Gradient Map will work correctly.

[Chri...@adobeforums.com]

If Gradient Map is working differently, most likely you have different color settings.
(the code hasn't changed)

[aska...@adobeforums.com]

Chris,
my color settings are same in CS3 (laptop) and CS4 (desktop) and gradient map is working differently as Kenneth described. I used to use GM to control total ink and colorize compositions, so its important tool for me.

[Mark_R...@adobeforums.com]

Its your color settings Edit/color settings - make sure they are the same CMYK in both versions.

Gradient map never actually produces 100c 0M,0Y,0K. Either CS3 or CS4. Both versions work the same way for me.

[aska...@adobeforums.com]

Yes, CMYK in both versions. CMYK working spaces: Euroscale Coated v2, all other color settings are the same.

And now the best things. I created project in CS3 (simply gradient map with C100 M0 Y0 K0 as one of value), save and then open in CS4... And gradient is OK! I checked info window - OK, then value in gradient editor - OK. Save and reopen - OK.
Conclusion. In CS4 you can operate on this kind of gradient map but can`t create it.

To Mark: Kenneth`s example is proof I`m not one and only.

One thing. Now I see this issue appeared in PS Mac forum and I work on PC/Vista64/XP. But I guess, it`s no matter.

[Ramón_G_Castañeda@adobeforums.com]

It matters quite a bit, askalski.

[Samuli_...@adobeforums.com]

Couldn't you get the same effect simply by going to layer blend settings and clicking the MYK channels off? Why use gradient map?

[aska...@adobeforums.com]

It was example only. I`d like to still use all my gradient presets.