Color management/correction

Greetings,

I must preface this post by saying that I'm an absolute rookie when it comes to digital print and the like. The firm I currently work with only recently started to dabble with printing, and we're still trying to find our way. It doesn't help that we are in a very small country/market, where you can't really get professional help and advice on certain issues.

So we have bought a used machine a couple of years ago, but only recently started to actively work on it. Once we got it up and running, we ran into a problem with colors. Now, as I said, we're not really a professional printing place. We don't really need the print to be an exact match for the photo or whatever we are printing. But the initial prints we did came out to be very unsatisfactory. I'll attach a couple of photos as an example.

Generally, the prints come out over-saturated, dark and often dominated by one color (it's kind of hard to see it in the photos, because apparently the camera I took them does some color correcting, but it's much worse than in the photos). Now, from my limited knowledge, I understand that to achieve a good print, you need good color management and calibration. Also, there's a lot of talk about .icc profiles, which I don't really understand how they work. I tried loading some general usage .icc profiles in the RIP application we got with the machine, but none of them seem to do anything or have any effect on the print. The only thing that affected the prints was playing around with the curves and ink limit. But the ink limit generally just made the prints look pale(r) and I really don't get how the curves work.

So are there any general pointers that people could give me? I know my best option would be to seek a professional, who could possible have one of those densitometer doohickeys, but where I live it's not really an option as I haven't found anyone who offers such services here. And as I said, I just need to get it to look "good enough", not really perfect or anything. So any advice is welcome. I'm also attaching a few screenshot of the color calibration options I have in my RIP application. Maybe it helps.
 

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chriscozi

Well-known member
Wow, so many things to start with.
First glance at the RIP screenshots begs these questions:
1. What press is this on?
2. What line screen ruling and DPI?
3. What kind of screen? (ie stochastic, chain, round, elliptical, etc)
 

SteveSuffRIT

Well-known member
Looks like an inkjet printer, not laser toner?
Do you know how to calibrate the printer? Usually a step b step wizard.
Do you have a service contract, can mfg rep come in to service?
Do you have a densitometer to check density and dot gain?
 
Wow, so many things to start with.
First glance at the RIP screenshots begs these questions:
1. What press is this on?
2. What line screen ruling and DPI?
3. What kind of screen? (ie stochastic, chain, round, elliptical, etc)

Thank you for your response. I'll try to answer the questions to the best of my ability (I apologize if I come off a bit dense, as I don't know all the terminology):

1. The printing machine in question is Agfa Anapurna M2050

2. These prints were done in 720x720 dpi (the maximum resolution for this machine is 720x1440dpi)

3. I'm pretty sure it's "precision stochastic screen", though there is also an option of "error diffusion" in a dropdown menu, which I have no idea what it means

Looks like an inkjet printer, not laser toner?
Do you know how to calibrate the printer? Usually a step b step wizard.
Do you have a service contract, can mfg rep come in to service?
Do you have a densitometer to check density and dot gain?

Thank you for your response.

It's a flatbed UV printer. It doesn't really come with any kind of calibration wizard. When I installed the RIP application, I selected my machine from the list and it automatically set up all the stuff as far as the width, length and resolution/number of passes. But there was no setup for the colors or anything akin to that.

Unfortunately, we bought this machine used and in disrepair from another country, and then worked on the mechanical issues it had until it started to work. As such, we don't really have any support for it in our country.

I don't have a densitometer. I noticed a menu in the "calibration curves" window specifically for densitometers. It has a list of 20+ supported densitometers. But even if I had access to one of those, I'm not sure I'd know how to work it. If I understand correctly, if I had the densitometer and used it, it would automatically find the correct calibration curves?
 

gordo

Well-known member
3. I'm pretty sure it's "precision stochastic screen", though there is also an option of "error diffusion" in a dropdown menu, which I have no idea what it means.

Precision stochastic screen and error diffusion are types of halftone screening. They are commonly called FM screens. They provide a more photographic appearance than regular "AM" halftone screens in print. They are they typical screens used on relatively low resolution printers like inkjets.

The distribution of the halftone dots with a "precision" stochastic screen is more ordered than an "error diffusion" stochastic screen. For your purposes the difference between the two screens will likely be in the visual appearance of the final image and the processing time. The "precision" stochastic screen may appear smoother but the "error diffusion" may appear sharper.
 

Bly

Member
Inkjets usually need custom profiles.
Buy an i1 spectro and learn to create your own profiles.
It's quite easy in Onyx, not sure about Caldera.
 

Puch

Well-known member
As Bly said, the easiest way to achieve acceptable, repeatable color is to use some kind of instrument. There are a ton of oldish i1 spectros available on ebay, which might be out of certification, but for your goals, they will suffice.
 
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Thank you all for responding. I'll try keeping an eye on a spectro that's compatible with my RIP software (there seems to be a list of them in a dropdown menu when I go to "calibration curves"), though from what I looked, they can be pretty pricey.

Does anyone have a link to some kind of guide how to operate one?
 

Correct Color

Well-known member
Art,

Wow...

I'm going to give you some advice right off the bat that I know from years of experience you won't take, but it is the best advice you can get and in the end it would prove out to be the cheapest route you can take, and that advice is:

Hire me to come set this up for you. It's exactly what I do for a living, and I could get this up and going for you in a couple of days.

That said, what you've got there is a combination of an old design and not particularly popular printer, and and old design and not particularly popular RIP.

The printer is what's known as a UV 'hybrid' printer in that it dries/cures its ink with UV light, and it can run either roll or rigid stock. It is, of course an inkjet printer.

A RIP is a Raster Image Processor. Its basic function is to convert the pixels you see on your screen that make up the image you're viewing into the dots you see on media that make up the printed image you're creating.

The RIP you're using is an old, cheap, bare-bones RIP called Wasatch.

The way a RIP converts information in digital images into dots, is using information in profiles. And in digital inkjet printing, for every specific printing condition, you need a profile describing that condition. You can use what are called stock profiles, but in order to sue them, they have to be made for your specific RIP.

If there are stock Wasatch profiles out there for an Anapurna, I would be very surprised. But you might check at Wasatch.com. That'd be the place to start.

Your only other option if they don't exist is to hire someone to make them, or learn to make them yourself. It's a long learning curve. Also while Wasatch had calibration tools included, it does not have an engine included to make ICC profiles. That you will have to buy separately along with a spectrophotometer.

If you want to learn everything you need to know regarding what it will take to learn to get to where you need to be, you might watch Color Management: The Movie.

That's about as comprehensive as it gets.

What you're out to do is doable, but the road is long, and the best way to never get there is to ask directions on the internet. There are many wrong turns, and many people online who will gladly steer you down them.

Good luck.


Mike Adams
Correct Color
 
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