How to convert from CMYK to (a few selected) spot colors?

J
Posted By
JGUni
Apr 1, 2004
Views
880
Replies
11
Status
Closed
Hi,

I am trying to convert a full color image to spot colors. The reason is simple: the image contains mostly blue and black colors and should be printed with minimum cost. So I am looking for a way to separate the full color image into a black channel and an arbitrary Pantone blue channel that together look as close to the original as possible. There does not seem to be a way to do this automatically or at least with some tool support.
So what I want is something like: "take this full color image and convert to a spot color image using this Pantone blue and black".
Any help appreciated.

BTW: Yes, I am a Phtoshop newb. 🙂

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John_Slate
Apr 1, 2004
You might try converting to CMYK, then copy the Cyan channel and paste it into a spot channel of the appropriate PMS number. Then fill the Cyan, Mag and Yel channels with white. Save as DCS2, unless you have the Creative Suite… then save as psd or pdf to place in ID.
J
JGUni
Apr 1, 2004
Thanks for your reply John!
Playing around with photoshop this morning, the same idea came to my mind. It works okay for one image (it’s quite simple, just a black-blueish gradient), but looks weired on the other. I worked on the other image and actually used the magenta (or was it yellow?) channel for black and cyan for blue. Still not too nice looking.
What bothers me most: this appears to be pretty much a standard problem, yet there appears to be no standard solution to it. Is there no tool that allows me to specify my own proprietary color model by defining the available basic colors and then tries to match the original colors as closely as possible? I know that there might not be one exact solution for each individual problem, depending on the basic colors specified, so the tool should find ONE that works.
CK
Christine_Krof_Shock
Apr 1, 2004
Convert file to greyscale Image>Mode>Greyscale. Then Image>Mode>Duotone. Set dialog box to Duotone choose your 2 spots.Adjust color curves for each spot. This might give you better tonality than multichannel.
AB
Arron_Boss
Apr 1, 2004
A Duotone is the answer here.

Arron
SW
Susan_Walters
Apr 1, 2004
There is a plugin that does exactly what you describe, but I can’t remember the name of it. It’s been 5 years at least since I saw it advertised, so I don’t even know if it’s still around. It will make custom duotones (or multi-spot color images) just the way you describe. Keep searching for it, in places where you find other 3rd party Photoshop plugins.
BO
Burton_Ogden
Apr 2, 2004
JGUni,

I think the Photoshop plugin that Susan is referring to is CreoScitex’s Powertone 1.5. I would post a link to some amazing examples of Powertone’s output, but the server that CreoScitex uses is woefully inadequate, and it would take "forever" for the webpage(s) to open. Powertone was originally created by a company called Intense Software and, as I recall, version 1 was for Photoshop 3. But CreoScitex either absorbed Intense Software or just acquired Powertone and Silvertone (a similar companion plugin for metallic inks) from them.

CreoScitex originally released Powertone 1.5 for Photoshop 5 and it hasn’t been modified or updated since. Version 1.5 had a distinctly better user interface and maybe a dozen other improvements. There were plans for a Powertone 2.0 with some killer new capabilities (2, 3, 4 or more spot colors with possible metallic ink capability) but I think there must have been "creative differences" and the programmer(s) left for greener pastures, or were "downsized", leaving Powertone now essentially unsupported (in my opinion).

Powertone can do amazing things with two inks. Here are a few links:

Powertone by CreoScitex plugin for Adobe Photoshop < http://www.adobe.com/products/plugins/photoshop/powertone.ht ml>

Powertone listing at PlugInz.com < http://www.pluginz.com/index.php?product=0000010882&from =rlist>

Adobe FAQ for Powertone by CreoScitex < http://www.adobe.com/products/plugins/photoshop/faq/powerton efaq.html>

Mini-review of Powertone 1.5 <http://www.freephotoshop.com/html/intense_software.html>

Powertone CreativePro listing <http://www.creativepro.com/software/home/656.html>

Powertone plugin for Photoshop < http://www.pluginsworld.com/Photoshop/plugins.php3?action=so ftware207&soft=Photoshop>

CreoScitex has a free downloadable trial version of Powertone 1.5, but it is limited to only two separations before it requires a purchased serial number. Perhaps you could get something useful with those two free outputs. We are now entering the slow service of CreoScitex’s sluggish server.

Powertone demo download form < http://www.creo.com/global/products/software_solutions/creat ive/powertone/Powertone%20Form?countryid=global>

In case you want to further explore within the limitations of that slow server, here is a link to menu of a gallery of some amazing sample separations, classified by ink-pair combinations. You are not limited to those simple ink combinations and, indeed, you can choose from the Pantone spectrum.

Powertone image gallery < http://www.creo.com/global/products/software_solutions/creat ive/powertone/powertone_gallery>

Here is a sort of home page for Powertone 1.5, once again subject to slow server service:

Creo Powertone Version 1.5 < http://www.creo.com/global/products/software_solutions/creat ive/powertone/default.htm>

Powertone 1.5 is not cheap, but Publishing Perfection discounts it:

Powertone discounted by Publishing Perfection < http://www.publishingperfection.com/productdetails.asp?sku=I SW112>

Refer to the FAQ link < http://www.adobe.com/products/plugins/photoshop/faq/powerton efaq.html> for information on the two file format options that you can output from Powertone.

In my opinion it is a major tragedy that Powertone’s development stagnated, because as good as its current two-ink cabilities are, the planned Powertone 2.0 would have been truly revolutionary, and even more exciting developments would have logically followed in subsequent new versions. I think we should be up to at least Powertone 3.0 by now. But alas. What went wrong, CreoScitex?

— Burton — (not associated with Powertone, Intense Software, CreoScitex, or any other vendor mentioned or linked)
J
JGUni
Apr 2, 2004
@Christine & Arron

I tried my luck with duotones aswell (even before fiddling with multichannel), in my case the results came not so close to what I could achieve using the trick to replace the cyan channel with a spot color. Maybe someone more proficient with doutone tweaking could do better. I will give it another go.

@Susane & Burton

That was exactly what I was looking for! Alas it seems quite expensive and I am from Europe. I will see where I can get a hold on the software for a reasonable price.

You have all been very helpful, thank you again.
DP
Deborah_Palmer
Apr 5, 2004
I’m new to this Photoshop thing and have also tried to produce a spot colour ad. I converted my image to grayscale then to duotone and applied cyan as one of my duotones then dragged and dropped it into my main image as a layer. However when I printed it i could clearly see yellow in image and when I checked the channels all four colours were available and showing.

can anyone explain this to me and give me the best solution?
RL
Robert_Levine
Apr 5, 2004
The only way to print spot colors is on a press. You can’t do it on a desktop printer.

Bob
BO
Burton_Ogden
Apr 6, 2004
I wish some printer manufacturer, like Epson for example, would come out with a desktop printer that could do spot colors.

— Burton —
B
Brian
Apr 6, 2004
You might try converting to CMYK, then copy the Cyan channel and paste it into a spot channel of the appropriate PMS number. Then fill the Cyan, Mag and Yel channels with white. Save as DCS2, unless you have the Creative Suite… then save as psd or pdf to place in ID.

That’s way too many extra steps. While in CMYK, drag the magenta and yellow channels to the trash – this will eliminate the unused channels and convert the file to multichannel. Double-click on the cyan channel and choose your spot color. Save as DCS. No copy & pasting, no extra unnecessary channels in the final file.

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