Question: BW photos on a Mimaki/Onyx PosterShop combo

[jmb]

I'm not sure if this should go here or in color management, but perhaps someone will know if the problem is with the inkjet or with the RIP? I have a problem where, when we output grayscale tiff or jpg images, if the output is not set to grayscale, there is a kind of moldy-looking color cast to the print ( kind of a mint-green in the light areas and purple in the shadows) and if it is, then they come out washed out and weak due to only being in K. I've tried the different ICC profiles in PosterShop, and they all come out identical, no visible difference between any of them.

When I look at the paused output, I can see that the problem is that the neutral color is being made up of a combination of magenta and green, primarily. We don't want sepia tones, we want a rich but cool gray so that the shadows will be dark enough, but still neutral. I've tried manually editing the RIP color Filters, lowering the magenta, pushing up the cyan, increasing the yellow, and all that does is make the purple-green color cast more pronounced, or start turning it into a sepia. I've played with the original converting it to a duotone in Photoshop, and I've run about 15 samples with different ICC profiles and other settings, no luck, and my boss is getting impatient with my trial-and-error.

Has anyone experienced this either with the Onyx Postershop RIP or with a Mimaki inkjet? Any known fixes for this? I appreciate any help!

 

[PrePress Guru]

I dont know if this helps but when i need to print a greyscale image using my Onyx ProductionHouse 7.2 and my Epson 9880 or HP 5500.
I have to convert the image to RGB using Adobe RGB 98 and then desaturate or the colors sometimes come out funky.
Remember that you have to at least run a re linearization before you can get accurate grey output. If you dont, then all bets are off.
Its better to re profile also to get optimum results.

I dont know why but Onyx has so many bugs its ridiculous.
Onyx has now taken the stance that they will not give us update or support unless we pay for a contract.
I would have no problem doing this if the RIP was even close to stable or use friendly.
After almost 2 years of version 7 we still dont have a media manager manual and the wiki is a horrible joke.

-ian
PrePress Express
Drum Scanning, Fine Art Printing, Pre Press & New Equipment Sales

 

[Ford Prefect]

PrePress, what problems are you encountering with ONYX?

 

[PrePress Guru]

Ford (Love the Hitchhikers series!),
The list is long and complicated. For one, the complete lack of documentation on the products.
2. The Auto rotate feature does not work at all with the Epson 9880, even though it was on the feature list.
3. The Layout app has a lot of bugs in it, it never prints out anything the correct size on the 9880.
4. The new Onyx support options make me sick! They have not corrected any of the bugs that have been plaguing users since version 7 came out. Now they want us to pay for updates and support. What a joke! I see no reason to continue to support them at all.
I have spent a lot of money for this rip and i have what i consider a Beta product.

There are so many more.....
That said, Onyx is still better than the other rips i have tried, not by much though.

-ian

 

[paul@dpiartservices]

It sounds like profiling issue to me.

I understand you can run straight from the Mac and bypass all color management settings. I haven't done it, but a client needs this soon, so we'll be trying it out.

We also run the UT3D inks on one 9800 that is set up specifically for B&W printing. I run Photo Black so when we have the need, they look fantastic. Otherwise, we run fine art watercolor paper there.

Good luck, and if you would like to see a sample off our UT3D machine, let me know!

Paul

 

[guru]

This is a colour management issue. Onyx is very colour specific in its setup which is a good thing but creates a few headaches. Your problem is NOT a bug of onyx it is a bug of the entire colour management concept in terms of what we know of colour.

The best thing to do is create a new profile what you need to be aware of is the GCR settings (grey component replacement) Basically it is the idea of using cyan, magenta and yellow to make grey.
If you just print with black to get grey it looks like someone through pepper on the paper, evan at high a quality. The general issue is if your profile is not perfect (non every are) you get a colour shift of neutral colours to a blue/greeny colour or the oppiste pink.

There is an option to create a media model for grey balance. I suggest create a seperate profile just for grey prints. it balances out cmy to give more neutral grey but pulls everything done making other colours look flat. once you create a grey balance model then create or icc.

step 1 Ink limits (this is an important stage mistakes can cause a poor result)
step 2 linerzation
Step 3 Create Grey balance
Step 4 Create ICC
Step 5 Choose the optimum GCR settings

To illustrate how GCR works go into Photoshop choose edit, color settings under the cmyk choose custom profile. The grey ramp is how the GCR will work. In the black generation flick between the options to get a clearer understanding.

I would like to take the opportunity to thank onyx for this cool feature other rips give shit all help with this problem.

Post me if you need more help.