rich black culprit

[G4pj]

Looking to see if anyone else has come across an issue when accepting files (pdf) from customers. File is supposed to print black plus spot, in reality, file prints spot plus C:75 M:68 Y:67 K:90. That means all the black text prints as a 90% screen.

I'm able to correct it, and get 100% output. However, the questions remains, how did it become supported black in the first place? I suspect the Auto swatch that word processors use could be the culprit. When I tested this by placing text into InDesign with Auto swatch, text was converted to black.

In the case of the first 12 page pdf newsletter file that came in. The first person to start working on the file uses Pagemaker, so placed text comes in with Auto swatch. I'm not sure what the second person who tweaks the file uses. In the case of the second file to come in (completely differenct source), a black plus spot form, the file was originally setup in Word, and I got both the Word and the pdf files. I was able to come up with a solution to place the pdf files into InDesign (documented and tested for repeatability) and convince the software that 100% black did appear in the document for before outputing to plates, I just want to know what is causing this phenomenon to occur.

thanks
pj

[The Repro Kid]

Howdy G4jp, I get this at my work all the time.

The reason it comes in this way is because black in Word is pure RGB black, R=0, G=0, B=0, the blackest black available in RGB. When this is pasted into an adobe CMYK document (ID, illus, or PS), the adobe app uses the adobe color settings to convert the RGB black into D-Max black, the blackest black available in CMYK.

Adobe aaps convert the text color to not what I would refer to as rich black, (rich black is a carefully thought out formula) but to what I call D-Max black (for lack of a better term), which is the blackest black you get from your color settings, the same black you'd get in photoshop when using default black in a cmyk image.

I made myself an action in Illustrator that I run on all text imported from word. The action resizes my text and does some other things I need, including turning my text to 100% black.

[G4pj]

I had picked a habit from my boss, he calls rich black and any other black with CMYK formulas, supported black.

I found it odd that when searching on C:75 M:68 Y:67 K:90, some folks were giving out this formula as a print guide for "Rich Black." Most print professionals go with a formula of 100:40:40:40, or even 100:40:0:40, some claim the yellow does awful things to the color.

The fix was easy enough, used a blending mode. I made the remark, "Hey, I should document this in case I have to use it again." To which my boss said, "You shouldn't have to use it again, don't bother." Then to which I replied, "We have several customers, and there's no telling how any of their files will come in." He was stumped and was glad he didn't listen to me when I got the follow up file from a different source.

I wrote down the basics, and tested it later for repeatability, and the following day, the other file came in. The guy that set up the newsletter should have known better, the girl that set up the form is a newbie, and I'm working to guide her through to better things.

[DCurry]

That rich black could have been created by a profile-to-profile conversion. Even true 100k will break like that (or similar) if you are converting profiles somewhere along the way.

[The Repro Kid]

...I found it odd that when searching on C:75 M:68 Y:67 K:90, some folks were giving out this formula as a print guide for "Rich Black." Most print professionals go with a formula of 100:40:40:40, or even 100:40:0:40, some claim the yellow does awful things to the color...

The problem with your 100k, 40, 40, 40 mix is not that the yellow does horrible things, it's that it's not a balanced black. To have a balanced black the M and Y should be equal and the C should be approx. 10% more than the M and Y.

100K, 30C, 20M and and 20Y, would be more appropriate. Any time your C is equal to your M and Y you get a warm black. IMHO warm black is yucky (yes that is a technical term).

My favorite rich black is 100k and 40C with no M and Y. Simple, effective, and very rich looking. But it's really the pressman's preference.

C:75 M:68 Y:67 K:90 is not a rich black, it is the fullest shadow tone available to what I'm guessing is the swop coated color profile. Special points to anyone that noticed how the M and Y are equal and the C is approximately 10% more than the M and Y in this formula. And even more extra points if you noticed that these numbers add up to 300, the D-Max for the swop coated profile.

This D-Max should be used sparingly, such as in the fullest shadow tones of an image file, as it represents the most ink the press can handle.

The fact that “folks” were handing out this number as a rich black shows you how little most “folks” know about printing. Ask a pressman about rich blacks and you will receive a far more realistic answer -- and I guarantee you there is not a pressman in the world who would request c75, m68, y67, k90 as a rich black. If he does, he's fired! :D

What DCurry is saying about conversions is what I'm talking about when I say color settings. Any time you convert color modes your image gets put through your specified color profile and the blacks are redefined. If you carefully prepared a photoshop file to contain 100% black is certain areas and then need to convert it to RGB to run some filters on it, when you convert back to CMYK, your 100% blacks will be replaced by your color setting's d-max black.

The formula for rich black really is the Pressman's call. It's what he prefers to run. Although it is to your advantage to know about balanced black, warm black and cool black. This way if some pressman request a 100:40:40:40, or a 100:40:0:40 rich black you will be tipped off that you may not have the best printers in town and may want to look for a better one. 100:40:40:40 = warm black, yuck. 100:40:0:40 = cool black to the point of being an almost purple black -- again, yuck.

Stick with things like: 100:50:30:30 or 100:30:20:20 or my personal favorite, 100:40:0:0.

It's not a good sign when your printer suggests unbalanced black values.

[G4pj]

In reality, I have had no opportunities to set up a file that uses rich black. My work is 1 and 2 color when I get it, the other times, it's fixing other peoples files, and it keeps me hopping.

I know that the 75:68:67:90 combination is not rich black, but the total on the ink values is 300% which is the maximum suggested for printing to get a piece to dry in a reasonable amount of time.

Sometimes I think it might have been nice to have more of a Y2K issue, in order to cut down on the amount of bad files that get sent in for print.

pj

[G4pj]

RGB mode, the pdf was saved to RGB mode, the Auto swatch had nothing to do with it. indesign appears to turn Auto into black.

[The Repro Kid]

I'm wondering if a preference in InDesign is what is causing you so much trouble. See the screen shot below. In the "print/export" pop-up menu, it defaults to "print all blacks as rich black." Change this to "print all blacks accurately."

Sorry but I don't have time much time today to elaborate on details. I'll try to fill more info later.