Urgent advice on printing 4C black and white images required please...

spiritlevel

New member
Hello everyone - my first post here.

Im currently doing the artwork for a CD digipack and CD onbody that is made up of black and white images.

Looking into the best way of doing the separations... The job will be printed on uncoated stock and there is no opportunity for proofs - and it needs to be sent off tomorrow...

Have been reading around this and other forums and various methods have been suggested which I have been trying out and looking at the resulting separations - but I'm still unsure which method to go with. The aim is to get strong punchy images but maintain neutrality as far as possible.

Options are:

1. Greyscale
Pros: certainly neutral.
Cons: images may look a bit flat, lack in contrast and blacks may not be very black, particularly on the uncoated stock as total ink coverage limited to 100%

2. Regular CMYK
Pros: stronger ink coverage, more contrast
Cons: images could easily take on an unwanted hue if press has any bias - did this before once and resulting images had a sludgy green hue which was not good - this is not really an option

3. Custom CMYK - high GCR
Certainly better than option 2 - but when I tested this last night there were till some areas of the image that made me worry about colour shift in the lighter areas - I got a reading of 12C 5M 5Y 2K at one point on the image which is unlikely to be neutral... also the cyan reading always seemed to be 8-10% stronger than M & Y consistently throughout the image which again made me worry about things taking on a cold tone.

4. CMYK - but remove CMY altogether from lighter areas of the image
Colour shift is not such a problem in dark areas of the image where there is lots of black coverage - it is the lighter areas that cause the problem. I found forum member Rich Apollo's PS action from this thread http://printplanet.com/forums/adobe/27462-cmyk-variation-software - which does a good job of this of removing CMY from lighter areas - CMY does not start to kick in at all until K hits about 25%. After that the CMK values are basically equal to each other (cyan maybe 1 or 2% stronger than M & Y) and the CMY values are consistently about half the K value throughout the image (after the initial 25% threshold has been passed). I like this option as the lighter areas just use black so no colour shift but in the darker areas the black gets underpinned by CMY so it has some punch and contrast - probably my preferred solution right now.

5. Greyscale images, but apply rich black swatch to them in InDesign
This is another interesting approach that I came across last night (forget exactly where) that I had not thought of. Use a greyscale image but apply a rich black swatch to it (example used 20C 15Y 15M 100K) in inDesign. I've used this method to colourise greyscale images before but never to turn a greyscale to a rich black. I like the fact that this method controls the CMYK balance consistently throughout the image - for any point the CMY value is always going to be 20% (C) or 15% (Y & M) of the K value. If I had the opportunity to do a scatter proof using different rich blacks then it would allow me to precisely control and test to get the exact look I wanted... But that's not an option here and I still have some concerns about neutrality in the lighter areas with this method...

So - I'm currently tossing up between option 4 and option 5 - what do you think would be best given this specific scenario? anything I've not thought of? All and any advice appreciated...

Who would have thought printing and black and white image would be so much more complicated than colour!

By the way, duotone/tritone is not an option here as the same image is repeated on both the cover and the CD body. While I could duotone the cover, I don't think the manufacturers can duotone the CD - It's either 4C or solid screen print.

thanks
 

Tommyjt

Well-known member
I have some heavy GCR ICC profiles that I made from GRACoL characterization data that would work great for you.
I would be happy to send them to you, just PM your email address.

Tom
 

Alith7

Well-known member
My company's specialty is multimedia packaging, and we work closely with one of our areas larger reproduction houses.
If you want to email me the art I can take a look and give you some suggestions.

that said, safest route by far is greyscale. with 4-color you run into a lot of touchy scenarios. if the calibration is off from the print house to the CD printer, you could end up with two different shades of black that won't match. Also, with reversed out white text and 4-color blacks, odds are VERY high that you will end up with colored "haloing" around your white type. there is a manual method that my shop does to "trap" that white text to avoid that. but a lot of companies don't do that. I can go over that with you if you decide that 4-color black is the way to go.

if you do go greyscale, there is one thing to keep in mind, ESPECIALLY on uncoated paper. once you get up above about 93% or so, it all fills in to 100% to the naked eye. On a coated sheet, it's about 97%. so you may want to adjust your photo curves to "open" the higher percentages a bit. leave 100% at 100%, but pull it back a little on the 80%+ range.

That's my 2cents.
 

Alith7

Well-known member
for manual trapping, (works best in illustrator) select your text, copy, paste behind. change the fill to 100% black and the apply a .5pt stroke of 100% black. DO NOT over print these, or it will completely defeat the purpose. Depending on the font, in the stroke palette, you may need to change the corner handling to rounded or angled if you have weird spikeys showing up from the stroke.
that's it, but it can be putzy! if you have a stroke on something already, just at .5pt to the line weight you already have and it will create the same effect.
you can do this in Indesign but it's a bit clumsier, and you have to be careful that indesign doesn't adjust the letter spacing to accommodate the stroke.
To "check" how this is working, turn on separation preview and toggle turning black on and off. when you turn it off, your white text should look "fat". when you turn it on it will look normal.

What this does is pulls the CMY separations back a hair (literally) so that if the print is a tick out of registration (it usual is) you won't get color haloing. but, even if it is actually perfectly registering, you won't see the difference. it will also help to keep you font edges smooth, instead of having the dot pattern from the screened CMY. You can use this same method for colored text and lines too.

in opening up the higher end screens in regards to 4-color, yes, I would pull them back a bit. uncoated papers tend to have more "spread" on the dot causing more dot gain and the higher percentage coverage to "plug" more. What you are seeing on you screen is equivalent to printing on a coated sheet, uncoated tends to be darker because to the nature of absorption of the ink on the fiber. not a lot, just a couple percentage points on a smooth scale.
 

spiritlevel

New member
Just want to say a big thank you to Rich Apollo, Tommyjt and Alith7 who have all been extremely helpful.

Artwork now done and off to print in the morning.

Fingers crossed!
 

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