Converting CMYK or RGB to Pantone colors?

[joshuac]

Hello. I realize that it is very difficult to come up with an algorithm that will examine a CMYK or RGB image and decide how to map that to a Pantone ink. When I convert an RGB or CMYK image to a Pantone ink with Pitstop, it ends up screening the image much lighter than I want. And I don't believe I have any control over how it makes this conversion. If I could apply some kind of curve after the fact, that would probably work. Absent that, I'm trying to find the next best workaround. I've tried using the Touch-up Object tool and changing the image in Photoshop by setting it as a monotone image. I've had some success with that. But I find that not all images will open with the Touch-up Object tool. And, of course, it's time-consuming. I thought to convert all type to outlines and then open the file in Illustrator. I thought there was a way to assign spot colors to objects in Illustrator, but maybe I'm mistaken. Are there any applications or plug-ins where you can select an RGB or CMYK image or line art and convert it to a Pantone with greater success? Thanks in advance.

Edited by: Joshua Cedar on May 28, 2008 12:09 PM

[TimP]

If you use the pitstop inspector you'll have to slide the colour bar to 100% after you've made the change.If you use the pitstop global change tool it will automatically be 100%.

open pitstop global change - colour / configure / grab fill / load / run change

[almaink]

With the CMYK image I would remap one of the process colors to the spot in Pit Stop. Pick the process color with the tonal range you want.

[joshuac]

Thanks for the response Tim. However, my image is a continuous tone image, so I don't get the slider bar.
Thanks also, AlMaink. With regard to remapping the various color separations to the Pantone color, I don't seem to be able to do that. I select the image, go to Inspector, and then Image > Remap. I can then set the Magenta Plate (which has the most information) to remap to the Pantone color. However, the Apply button is greyed out. Also, I would probably need to set the other separations so that they are discarded. I'm not sure if that's doable. Can you tell me more about this process?

[almaink]

Could be your color mode, I just tried doing this with a process tif and it worked. Only problem is you can't see the change unless you use separations preview. Kind of an odd thing you want to do, not that I haven't had odd requests, but I think this type of thing should be done in the native application. Perhaps export all images, and then alter the image in Photoshop and save it as either a psd with spot channel, or as an eps duotone. Place the PDF into InDesign, then place the new altered image on top of the PDF using the old image for placement. Edit the PDF in Acrobat to remove the old image and save. Re-export to PDF from Indy.

[joshuac]

I have a printing business and we receive many files that have color space issues. It is often faster to fix them ourselves, rather than wait for a customer to fix the file and resubmit. That being said, fixing in the native application certainly would resolve the issue.
With regard to your idea, I was able to change one plate to the Pantone color. But if I chose more than one ink to remap, the Apply button was greyed out. I tried converting each separation, one by one. But after the first remap, the apply button was always greyed out. The remapping still leaves the other separations, so I have to delete them or remap all of them. That puts me back at square one.
I could just choose the image and select spot color in the Inspector, but the conversion makes the image much lighter. It has to do with the conversion process. Pitstop converts to greyscale first, simulating the color with tints of black. That eliminates the shadows, because even the darkest part of the color image is simulated with a tint of black. There are no values in the image darker than 85%. I realize that there may not be a good answer for this issue. But thanks for the help.

[PDQDUNDEE]

Sorry if I missed something earlier but can I ask what is the final result you need? Is it as simple as wanting to create two plates for a two spot colour print from a mixed up RGB / CMYK file that has been submitted?

Peter

[joshuac]

I'm actually attaching a sample portion of the page. You will see that there is some Orange line art (Pantone 158) and a background image that is supposed to be in Pantone 158, but is a CMYK image. You can select the CMYK image in Inspector, click on Spot Color, and choose Pantone 158 from the Document Spot Color list. However, it becomes much lighter because of the conversion process Pitstop uses (CMYK > Grey > Spot color) that I described above. So I'm trying to figure out a way to end up with an image with similar contrast to the original CMYK image. I mentioned that TouchUp Object is one way to do it. But I'm looking for a faster, easier way. The goal is to end up with a file that will separate into Black and Pantone 158. Thanks.

[JohnM]

try this.... it's in between pitstop and the file u posted, but it only takes two seconds to do....


won't let me post the file...

let me have your email I'll send it to you...

[joshuac]

My e-mail is joshc@newsletterexpress.com