Question Been doing this for years...................

[Gino]

For years, when we print to our flatbed, we would use CMYK black, all black, rich black, RGB black and just about any combination we wanted to. However, recently..... it seems, unless I use CMYK or just black, it comes out kinda like a very very dark brown. Now, our flatbed is 6 colors and has light magenta and light cyan, but the rip just says CMYK. It is Wasatch. I can use the same file and go to our Roland and it will all still print black. Seems as if RGB will not produce black anymore on the flatbed. I was printing a job out last week and I thought one of the heads wasn't firing correctly. Turns out it was. After I tore the supplied file apart, I found the logo was in CMYK and the copy was all from another program and using RGB. I started testing and found this to be kinda true in about 6 tests so far.

Any ideas or fixes ??

Gino​

 

[Adam Vreeke]

If you are using Illustrator:

Edit > Preferences > Appearance of Black.

I have my settings at:
On Screen: Display All Black Accurately
Printing / Exporting: Output All Blacks as Rich Black

This way if someone sneaks in 2 different black I know and it outputs them all the same. Unfortunately it shows RGB Blackk as Rich black so it is harder to tell. I haven't tested the output at all if there is RGB and CMYK in the file, but this is where I would start.

 

[Gino]

That's exactly where my settings already are set.

 

[Boudica]

hmm, I know how you could even that out in Onyx, but i'm not familiar with Wasatch.

 

[Adam Vreeke]

That's exactly where my settings already are set.

Then I am unfortunately out of ideas. Perhaps you should ring up Robert Armerding for guidance on such an issue? Or have you perhaps tried listening to your machine to see what it is telling you?

Edit: Try opening the file again for me as it was sent. Go to Windows > Separation Preview. Click Overprint Preview on turning the individual channels off to see if that turns it on / off.

 

[White Haus]

Not familiar with Wasatch either, but perhaps something changed in your rendering intents so that RGB and CMYK are interpreted differently?

I dunno...

 

[Zach Starr]

It might the profiles are not working properly, having tried making a new profile on it. There might be some error on your current profile causing it, i had experienced that with some grey tonnes. You can try that out.

 

[Gino]

If I print at fast mode, colors are never where they should be, but normal production or some of the high end profiles should always produce black as black. It's a dilli (much like an Agfa), not latex.

 

[Pauly]

Are you saying 6 colour as in CMYK Lm Lc ? as that's considered as 4 colour which is why it would say CMYK in the rip.
If it has Orange & Green etc, it may just say CMYK as it's still a CMYK base printer.

Anywho,
I've had some odd stuff though RGB black and CMYK black before. CMYK prints black but not as 'rich' as RGB Black, but never brown.

I can only suggest doing some rest prints with different kind of blacks.

Also try re-linearise the media profile or make a new one and see if it does it.
Over time the heads characteristics do change

 

[GB2]

If you are using Illustrator:

Edit > Preferences > Appearance of Black.

I have my settings at:
On Screen: Display All Black Accurately
Printing / Exporting: Output All Blacks as Rich Black

This way if someone sneaks in 2 different black I know and it outputs them all the same. Unfortunately it shows RGB Blackk as Rich black so it is harder to tell. I haven't tested the output at all if there is RGB and CMYK in the file, but this is where I would start.

So I just noticed for the first time that this setting says, "Options for Black on RGB and Grayscale devices", which implies to me that this setting has no affect on outputting to CMYK devices and therefore will have no affect on how something prints Black on a CMYK printer. Here is something I found that seems to confirm this:

If you are creating artwork for print I would urge you to change the On Screen setting to Display All Blacks Accurately as this will give you a more reliable display that closely represents how blacks, both single colour and composite, interactive with other colours in your document.

Depending on the set up of your printing device you may find that the Print/Exporting setting has no impact. Printing devices configured with colour management will tend to use CMYK colour as their input source so the Preference setting is ignored as it only applies to RGB devices.

More basic printers, like standard office printers, tend to use RGB as their input source so this setting will come into effect in this scenario.

As this second option applies to Exporting as well as printing you may need to change this when exporting a CMYK graphic to RGB. However, this would only be necessary if you actually wanted to see a difference in the black elements in your graphic. For the most part black tends to be rendered as rich black with on screen graphics. When viewing black text in a web browser, for example, you will be viewing a full-strength RGB black so only change this setting if it’s relevent.

I think you are probably better off leaving the setting to display accurately and print accurately, that way at least what you see is what you get and the program stands no chance of altering your colors without you realizing.