Creating a step tablet in photoshop

I am trying to create a step tablet in photoshop like described at

 

http://www.bradhinkel.com/Correction%20Curves%20for%20Digital%

20Negatives.htm

 

to use in setting down some personal correction curves for printing

digital negatives. My problem is that using PhotoshopCS I will go to

the CMYK part of the color pallette enter in for example 0,0,0,34 for

the 34% grey box and fill it. The problem is that when I place the

mouse over the now filled box the info gives the K value as 29%. This

is just one example, but every box is wrong after 0%. Should I just

put in my K value in the color picker and ignore what the info pallete

says or should I adjust what I place into the color picker so that the

info pallete info comes out correct.

 

My monitor is calibrated, but I would think that this would have

nothing to do with it as whatever color shows up on my screen is

superfluous as photoshop should still be filling with a certain K%. I

don't understand why this is changing from the time I choose the color

to when I fill it. I am using Edit>Fill>Foreground Color.

 

The image is greyscale and I am working in Gamma 2.2 as that is my

normal colorspace for editing.

the link that you provided does not work

Jeremy's link has a space in it.<p>Try: <a href="http://www.bradhinkel.com/Correction%20Curves%20for%20Digital%20Negatives.htm">http://www.bradhinkel.com/Correction%20Curves%20for%20Digital%20Negatives.htm</a>

I'm not sure what you're trying to do, but I can tell you how to

create a step scale, that you might be able to cut up and use.

 

create a new window at whatever size and mode you want.

 

make a linear gradation, white to black, and by holding the shift

key ddown, you'll make it straight across your window.

 

Go to image> adjust > posterize, and specify how many steps

you want.

 

Hit OK, and you'll have a stepped grey scale.

 

good luck!

OK, I'm looking a little more at what you're trying to do, pretty

clever if it works (consistantly).

 

I think that you should avoid working in CMYK. Repeat: Don't

work in CMYK unless your printer or RIP require it.

 

Most printers have their own conversions, that you don't need to

mess with.

 

Perhaps the reason that you can't nail down your values in CMYK

is the non-linear application of the K channel.

 

CMYK conversions are pretty specific to professional printing

processes using plates and aren't neccessary to printers that

run indivisual sheets of paper. The dot gain curve alone will kill

you.

 

Good luck.

Jeremy,

 

My guess is that your document is not a CMYK image. If not, the CMYK value you type in gets converted to RGB or grayscale, if that is what you are working with. The CMYK source is your default CMYK working space, the rendering in tent is your default intent. The info palette then translates the document colors to your default CMYK space using the default rendering intent. If you start with a CMYK document, fill with a color of (0, 0, 0, 34), that's what the info palette will read.

I able to work it out. I just created the first half to spec, inverted it, flipped it both horizontally and vertically and I was finished. My step tablet now reads perfectly on the info palette.