Highlight Midtone Shadow and all in between

[bob carnie]

Ok you photoshop gurus, here is a slightly more complicated question, but to the right person this may be the most silly question of all time.


When we separate in CMYK - we get four channels, one for black detail and the other three subtractive colours.

In the world of ink on press, UCR or GCR is used to lower the amount of pigment (costly) of the three colours by adding grey into the mix.. Therefore the three channels
are slightly off or better stated not as clear , clean and pure as lets say Red Green and Blue from the RGB separations .. by adding the black k the printer can make of more perceived image by the addition of cheaper black ink.

How do I take off UCR or GCR ?- as I convert and then split the channels I see no way of getting rid of this unwanted noise. But this may be as easy as pie, but it alludes me.

I think Greg will have the answer but lets see..

[andy]

Ok you photoshop gurus, here is a slightly more complicated question, but to the right person this may be the most silly question of all time.


When we separate in CMYK - we get four channels, one for black detail and the other three subtractive colours.

In the world of ink on press, UCR or GCR is used to lower the amount of pigment (costly) of the three colours by adding grey into the mix.. Therefore the three channels
are slightly off or better stated not as clear , clean and pure as lets say Red Green and Blue from the RGB separations .. by adding the black k the printer can make of more perceived image by the addition of cheaper black ink.

How do I take off UCR or GCR ?- as I convert and then split the channels I see no way of getting rid of this unwanted noise. But this may be as easy as pie, but it alludes me.

I think Greg will have the answer but lets see..

that's going to be handled by the specific CMYK profile you use--UCR/GCR in the color profile is preventing you from outputting a file with 400% washes of color, in practice though I've never seen this manifest as a real problem--I run a digital offset press (hp indigo) and have been making some experiments playing with the channels and such and haven't had a problem outputting solid washes of 100% color from photoshop--

[bob carnie]

Hi Andy

for my purposes I do not need UCR/GCR as I am doing pure pigment printing gum over palladium, my work is not going to any third party press.

There is no problem getting R G or B but C M and Y seem to have UCR/GCR and I want them clean for my purposes.
Can you point me to a CMYK profile listed in Photoshop that does not have this.

I am pretty sure there is a way of unclicking this function , but I forgot the way to do it.

not a very standard question. Think dye transfer and you will get where I am headed with this question.

Bob

that's going to be handled by the specific CMYK profile you use--UCR/GCR in the color profile is preventing you from outputting a file with 400% washes of color, in practice though I've never seen this manifest as a real problem--I run a digital offset press (hp indigo) and have been making some experiments playing with the channels and such and haven't had a problem outputting solid washes of 100% color from photoshop--

[andy]

Hi Andy

for my purposes I do not need UCR/GCR as I am doing pure pigment printing gum over palladium, my work is not going to any third party press.

There is no problem getting R G or B but C M and Y seem to have UCR/GCR and I want them clean for my purposes.
Can you point me to a CMYK profile listed in Photoshop that does not have this.

I am pretty sure there is a way of unclicking this function , but I forgot the way to do it.

not a very standard question. Think dye transfer and you will get where I am headed with this question.

Bob

It's under "Convert to profile"
set your profile as "custom CMYK" and it opens a dialog box with the controls.

[bob carnie]

Ok thanks - so is it pretty simple to navigate the controls?, I will give it a shot and may get back to you. Us Canadians are a bit slow at the beginning.

Samples of what I am doing are going to be in Brooklyn Photoville this fall I will be there on the 12th and 13th with my client.

Bob

It's under "Convert to profile"
set your profile as "custom CMYK" and it opens a dialog box with the controls.

[andy]

great! Photoville is a lot of fun.

here is a screen grab of the dialog box:


I suspect you'll want to set black generation to maximum and the total ink limit % to 400.

that should do the trick.

[bob carnie]

Ok so the post of Ken's (thanks) was used with great success over this weekend, I think it is a powerful tool for any Pt Pd printer who wants to introduce permanent colour on top of palladium platinum print

http://video214.com/play/nK7IAEMdbQmJVgCmxNGjTQ/s/dark

[bob carnie]

Hi Andy

I would like to discuss this further with you..

right now I am swamped but I would like to see no pollution of the C M Y channel with black

could you explain or demo a bit more your thinking as it is not obvious to me how this will work.

thanks
Bob

great! Photoville is a lot of fun.

here is a screen grab of the dialog box:


I suspect you'll want to set black generation to maximum and the total ink limit % to 400.

that should do the trick.