Konica Minolta C6501 is converting greyscale pdfs to color

[lexcreate]

Let me explain...
I printed a 192 page book on the C6501 and noticed on my utility counter that the Fiery/Konica was seeing the greyscale images as color. This was after I had converted the cmyk grey image to greyscale in photoshop. It also reads the black and white pdfs that I originally created in illustrator as color as well. They don't print in color, but for some reason when I print the utility counter it reads those images as color. (Of course, we will be charged for that as well). Why would it do this?

Any suggestions on proper output would be helpful. Just wondering if exporting an .ai file to a jpeg would help. I'd like to avoid .tiff images because eventually this printed book gets converted to html and uploaded to the web and I'd like a steamlined approach to the output process.

[Londen]

make sure you turn off the crop marks. RIP sees crop marks in "Registration" color which mean CMYK.

[arossetti]

PDF's that you convert two greyscale do not convert to pure black. It will use CMYK toner to create grey (composite).

If you do not use pure black in making your documents in illustrator it will print using all 4 colors to create the black (composite).

The other option could be your color workflow in your fiery rip. Check your settings to make sure your rip isn't setup to convert your greyscale images/text.

[CNewcomb]

There is definitely something in the PDF that is carrying over some color (probably indeed registration). Just change the color settings in the job properties in the command workstation to print grayscale and not CMYK. Then no matter what your file is you will not be charged a color click.

[Netrunner9]

Could you setup a seperate print driver for BW only as device default? I have done this on several other brands just not a KM.

[Digital Press Guy]

Let me explain...
I printed a 192 page book on the C6501 and noticed on my utility counter that the Fiery/Konica was seeing the greyscale images as color. This was after I had converted the cmyk grey image to greyscale in photoshop. It also reads the black and white pdfs that I originally created in illustrator as color as well. They don't print in color, but for some reason when I print the utility counter it reads those images as color. (Of course, we will be charged for that as well). Why would it do this?

Any suggestions on proper output would be helpful. Just wondering if exporting an .ai file to a jpeg would help. I'd like to avoid .tiff images because eventually this printed book gets converted to html and uploaded to the web and I'd like a steamlined approach to the output process.

The RIP is reading CMYK component somewhere in the file. It may have been created as CMYK grayscale or, have CMYK some place outside the image area such as in the crop marks.

I've been away from KM gear for a while now but if I remember correctly there is a command in the RIP that tells the C6501 to print black only. That should apply to either the Creo or the Fiery RIPs.

Good Luck...

[mattbeals]

Let me explain...
I printed a 192 page book on the C6501 and noticed on my utility counter that the Fiery/Konica was seeing the greyscale images as color. This was after I had converted the cmyk grey image to greyscale in photoshop. It also reads the black and white pdfs that I originally created in illustrator as color as well. They don't print in color, but for some reason when I print the utility counter it reads those images as color. (Of course, we will be charged for that as well). Why would it do this?

Any suggestions on proper output would be helpful. Just wondering if exporting an .ai file to a jpeg would help. I'd like to avoid .tiff images because eventually this printed book gets converted to html and uploaded to the web and I'd like a steamlined approach to the output process.

What I have seen with Konica's and Fiery controllers is that the Konica needs to see "device gray" blacks for a black click. But... The Fiery when sending a book like this will send the job to the Konica as a color job because there is color in the book. Regardless of the fact that 191 of the 192 pages are black only and only one is color.

If you're sending the job from InDesign then the blacks may be "separation black" or K of CMYK which would likely cause the same false click.

I use Callas pdfToolox to map all blacks/grays to device gray and that usually solves the problem. But since you've got both a Fiery and a Konica you'd have to test to see what the actuall click counts are. If you want me to process a job for you I'd be happy to.

[UberTech]

You could go thru some complicated method of converting your PDF's to colour and still find they print in colour. The best and 100% full proof method is to use the media manager in the fiery or exceptions in the creo to specfiy which pages are grey only. It is pretty easy to specify pages much the same as a any dtp package like 1,2,3,4,18-20,35 etc etc.

[lexcreate]

Thank you UberTech for the solution. This does work!

[Bo3b]

Not too sure about KM Fierys but I'm reasonably certain that most Fierys are the same.
If the CMYK simulation method is set to full you may get some colour in what were greyscale images - setting the simulation to quick (or maybe source gcr) will not mix colour into the greys. Also using a High GCR or even 100% GCR output profile will help in the determination of what constitutes a grey or not.