Expert: Glen Demers - 10/5/2009

Question
QUESTION: Hi Glen, I am working on a 2 color program (PMS 1795 and black). The problem I am having is with PDFs that I am pulling from an old program. They are RGB. I need to somehow make them grayscale while retaining the PMS 1795 color. Is it possible? I'm hoping you can help me, it would be greatly appreciated!!

Thanks!

ANSWER: Hi Michelle,

I'm assuming you are opening them in Photoshop, the only other alternative would be to open them in Illustrator for vector images, but this may cause font issues or fix them in Acrobat - but this would require a third party plug-in such as Enfocus Pitstop.

In Photoshop you'll have to convert them to multi-channel mode, create two channel files and save them as .eps files.

If you need further explanation, follow up and I'll explain in detail.

Hope this helps,
Glen Demers
Adobe Certified Expert, Photoshop 7
Prepress Technician, Best Printing Online
www.bestprintingonline.com

For more Photoshop tips please visit our help pages here: http://www.bestprintingonline.com/photoshop.htm

---------- FOLLOW-UP ----------

QUESTION: Yes, I am opening them in Photoshop CS2 and then pulling the PDFs in InDesign CS2 for the program layout. Please explain 2 channel files. Will the copy be could enough to print after pulling them into PhotoShop? Is Pitstop an expensive yet viable option? Thanks again for your time!

ANSWER: Hi Michelle,

Pitstop is essential for fixing pdf's supplied to us that are wrong, but at about $600 it is not for home use.

Open your pdf in Photoshop in CMYK color mode and 300dpi resolution. Go to Image>Mode and select Multichannel. You will now have to color break the file manually, most of the black information should be in the Cyan or Black channels and the red elements will be strongest in the Yellow and Magenta channels. Let's start with red, select the Magenta or Yellow channel in the Channels palette. You will see a grayscale image with red items darkest, erase everything that isn't red and go to Image>Adjustments>Levels. Move the left slider to the right under the histogram until the solid red areas are 100% black. In the channels palette, double click the area with the word Magenta but not on the word, this will open the channel dialog box. Change the name from Magenta to PANTONE 1795 C and click on the color swatch in ink characteristics to bring up the color picker. Click on Custom, Select a Pantone book and type 1795 or scroll to that color to make it the channel color. Click okay, okay. This will give you your red channel.

Command/Control click on the Red channel icon to select everything red. Select the Cyan or Black channel and hit delete to remove everything red from this channel. Pull up the levels palette and continue as above to make the Black channel.

Select the two remaining channels and delete them by clicking on the trash can. You should now have a two channel Photoshop file with a color preview. Save this as a Photoshop DCS 2 file, One file with color composite. Make sure the Pantone color book and name of the red channel matches exactly the red used in your InDesign document. You can place this files in InDesign just like any other .eps graphic.

You could also open the pdf's in Grayscale mode and make them Black and Pantone 1795 Duotones, but a duotone is one grayscale image with two sets of curves applied to it. It will give you a dark red picture but you'll have little control over the color breaks.

It's far easier to make the pdf's correctly the first time around or to fix the colors in Illustrator, but if you need to make RGB pdf's into two color ones in Photoshop, this is the way to do it. It will take some experimenting with levels, especially if you have elements that are blends of red and black.

Good luck and I hope this helped,
Glen Demers
Adobe Certified Expert, Photoshop 7
Prepress Technician, Best Printing Online
www.bestprintingonline.com

For more Photoshop tips please visit our help pages here: http://www.bestprintingonline.com/photoshop.htm

---------- FOLLOW-UP ----------

QUESTION: I have followed the steps above about 50 or so times and pretty fast working with channels. Thanks for taking the time to write out each step! There are just a few more PDFs to do and are a little more difficult. I attached an image for you to see what I mean. Would you use the same steps for something like this?

Answer
Hi Michelle,

I would follow the same basic steps, but once you have one color channel made, you can command/control click on it to make a selection and go to another channel. Make the background color white on the toolbar and hit delete. This will subtract your one channel from the next quickly and should speed up the process.

Hope this helps,
Glen Demers
Adobe Certified Expert, Photoshop 7
Prepress Technician, Best Printing Online
www.bestprintingonline.com

For more Photoshop tips please visit our help pages here: http://www.bestprintingonline.com/photoshop.htm