Fifth Color Channel

I am designing a book for an artist who uses very strong blue colors. I know that it is hard to tell the visual effect of the color from the small screen image. But when you see the original art and the printed reproduction on hand, you will see the difference. Printing the blue color with CMYK is the problem. The other colors come out fine.

I am thinking to use Pantone spot color such as Blue 072C with the mixture of CMYK. I tried to make a spot channel in Photoshop by selecting the Blue 072C color range and making it as the fifth channel. The problem is that I don't know how to adjust the CMYK amount behind the fifth solid color. The image stays the same when I convert to CMYK. In other words, it doesn't automatically recalculate the CMYK percentage behind the spot color. That means if I print it just like that, the Blue colored area of the image will come out very dark.

As the designer, am I responsible for figuring out the mix of the CMYK+Solid Color or do the press plate makers do it for me? I desperately need a help.

 

I assume that if you have a solid whatever color, adding anything on the background will spoil it making results unpredictable. If you had picked the PMS you think will satisfy the client and plan to print the job CMYK+1PMS, keep PMS color clear of any CMYK this way you should receive intended result. I am not a professional printer/designer but out of what I learned so far - I think this is the right way to do it.

 

Thanks for input

I understand what you mean. And I think some of the Pantone solid colors will work fine for the most part of the blue color, but there are some areas which go darker than the actual solid color's 100% value. Those parts definitely need a little more additional color from CMYK. I have to figure out how to fine tune those areas with extra nuances.
Still willing to hear other opinions and advices.

 

Have you tried layering the area and applying a"multiple" effect to create an "overprint" on your 072 of the
image?? That will at least show you close to how it will look, then adjust your color from there.

 

No I haven't tried any testing with the PMS. By the way what does PMS stand for? Sorry for the silly question but I know it is referring to the 5th solid color. I need to find the right amount of ink and a company who is willing to do the test. Nowadays most companies are reluctant to spend their time on small things.

 

Pantone Matching System. Ink rotation on press may also play a big part on achieving the visual effect you are after.

 

What is ink rotation?

Can you explain about ink rotation? I have no idea about it.
I am planning to use a custom color 5 th channel. There is a company that does specialty inks. But I don't know how much ink I will need to order. I am printing 1000 books. The book is going to be 300 pages, but it has about 60 pages with the custom inked images. The blue color will not take too much of the page. Mostly about 15-20% of the page. I will probably have to do some test run too.
Can any one help me to calculate how much of ink I need to buy?

 

Ink rotation is the allocation of inks on press. For example, on 5 color press i would run the pantone in the first unit and process in last four. K,C,M,Y. The company you are purchasing the ink from should know the formula for the amount of ink you need, at least ball park. Size of sheet, Coverage and type of stock all play factors in the formula. I know there is a calculator for it.