Platinum (Ziatype) over Pigment process - Part II - Image Prep

[JimCollum]

Part I gave a quick overview of what the process was, and gave an indication of that type of image might work with this process (not all do, by any means).

Part II will go over workflow steps to get the color image into the two parts necessary to create the print. You will need a digital negative (calibration of that won't be covered in this part) and a color layer printed onto a sheet of appropriate watercolor paper (will go over the types of paper a bit later)

Start with a color image. If you're trying this for the first time, then start with an image that has a full scale.. no high or low key images. This will just make it easier

Creating the image requires that you convert it from RGB into CMYK... this is the color space that has traditionally been used for printing. Your digital negative will come from the K layer, and the color will come from the CMY.

1. Load the image into Photoshop.. RGB & Adobe RGB color space.

2. You will need to create a custom CMYK color space for the conversion.
Edit-> Color Settings ...

3. In the Color Settings dialog box, select Custom CMYK in the Color Space CMYK pull-down
you should see something like:

4. The import part in this is the Separation Options.
Separation Type should be GCR
Black Generation should be Maximum
(title it anything appropriate)

5. Your Channels should look something like

6. You'll notice that the color has shifted.. become more 'mute'. The CMYK space isn't as 'vibrant' as RGB. This won't make much of a difference with this process, if you've selected an image that needs this vibrancy, then you've chosen poorly

7. In Channels, select the K layer. Then Image-> Mode-> Greyscale.

8. Once in Greyscale, you'll covert to RGB... Image-> Mode-> RGB Color
You should see the Channels something like

9. Save this as something like <filename>_platinum_negative.tiff

10 Go to your history and delete history steps Extract Channel on forward. This should bring you back to your full color CMYK image.

11. Now it's time to get the color info. Select the K layer again then Select-> All

12. You want to Clear this channel, not delete it.. so while the K is selected
Edit-> Clear

(ran into image limits.. continued next response)

 

[JimCollum]

13. Your channels should look something like

This layer should be very mute color, with no contrast/detail information. If not, then you've messed up on creating the CMYK color space step.

14. Now convert this back to RGB
Image-> Mode-> RGB Color

15. I usually put a contrast curve on this to increase the color saturation/contrast. You lose a lot of color going onto watercolor paper, so this will give you some additional color in the final print

16. These are the basic prep steps. You'll want to a curve & color screen to the negative (look into Mark Nelson's PDN digital negative system.. it's a good one) as well as registration marks . I'll go over that a bit next

 

[JimCollum]

Registration targets

I've found that I have more control if I add my own to the image, rather than use the Photoshop versions. I found some free actions that i tailored to my own workflow at

http://www.wilflexeasyart.com/downloads.htm

you'll want to make sure that these are in the same locations for both the color and negative files. I have two actions, one to print color with registration, the other to print negative with registration. I've modified the actions from wiliflexeasyart so that the colors are very faint on the color.. that way they disappear inside of the black platinum border

 

[Asher Kelman]

Jim,

I'm sitting in my seat while they refuel for takeoff from Paris to LA. j
Just a note to wish you a healthy new year! This contribution is so generous!

Thanks! I intend to be trying this out!

Looking forward to the posts that follow.

Asher

 

[Ben Rubinstein]

Not had a clear head to look through this properly though the concept and results are magnificent, as soon as I get my head straight I want to look into it properly!

 

[Ben Rubinstein]

Jim, this certainly looks very complicated! The results certainly look worth it though. The thing which worries me the most is the registration, it seems to be almost impossible to register to within about 300dpi or whatever resolution you use? How do you do it?

 

[JimCollum]

Jim, this certainly looks very complicated! The results certainly look worth it though. The thing which worries me the most is the registration, it seems to be almost impossible to register to within about 300dpi or whatever resolution you use? How do you do it?

The biggest issue is shrinkage (paper). presoaking the paper and letting it dry first helps. also, prior to putting it into the printer, i let it sit in my coating room .. usually at 70-80% humidity.

Then, the combination of having the color layer slightly blurred and getting the registration marks inline (having a vacuum easel helps keep them that way).

If you do end up with some slight mis-registration, it usually isn't noticeable, unless it's on the outside edge of the image. for this reason (as well as aesthetic), i usually keep the rough brush stroke outline on the print, rather than mask it off to give a clean white border

 

[Asher Kelman]

Sorry that the images are not showing. Will try to fix the links ASAP!

 

[Kerik Kouklis]

Thanks! That would be great.

 

[Asher Kelman]

Thanks! That would be great.

Kerik, as an experienced platinum printer, there's not a lot you would find new.

Still, just for completeness sake, for those who want to get started, here's the link to Jim's excellent introduction loaded with references to technique and helpful resources.

Meanwhile, I have reached out to Jim!

Asher