Press room query

Greetings to all Printers!

I just want to ask on what seems to be the problem with my machine K series one color press, as when printing a colored images through color sep the finish product seems to be a lot darker than the proofing I have.

Hope someone could help me on this.

What kind of proof do you have?

Archer wrote:

What kind of proof do you have?

Digital progressive proofing

soul2181 wrote:

I just want to ask on what seems to be the problem with my machine K series one color press, as when printing a colored images through color sep the finish product seems to be a lot darker than the proofing I have.

It is an accepted fact that dot sizes will increase when an image is printed on an offset machine. The increase in dot size is called DOT GAIN and is measured at the 50% area of an image. For example, if a 50% area is measured with a densitometer and the value is 80%; then, the dot gain is 20%.

Dot gain is included in the output ICC profile which is inputed into the proofing rip of a digital proofer. In a lot of digital proofer, a generic ICC profile is applied. These generic profiles usually incorporate a dot gain of 15 to 20%, which is standard. The proof would then reflect the dot gain and print a darker image.

I think the problem is that your old K series machine has a higher dot gain than that in the generic ICC profile of the proofer. I suggest either 1 of 2 things:
1. Adjust the rip of your proofer to reflect the higher dot gain or
2. apply a dot gain compensation at the imagesetter rip to bring down the dot values in the film.
(Don't do both.)

I will be conducting a seminar "Answers to FAQ's on Digital Prepress" during the Label & Print 2007 Exhibition at the World Trade Center on Sept 29 at 2 pm. The subject of Dot Gain will be discussed there. Attend kayo. Libre naman!

Is the traditional progressive proof more reliable than the digital progressive proof?

Archer wrote:

Is the traditional progressive proof more reliable than the digital progressive proof?

In my opinion, the traditional press proof is more reliable because it uses the same ink, substrate and printing process as the final press run. However, a press proof is a more expensive and time consuming process than the digital proof. Furthermore, if there are corrections to the proof, you will have to redo the plates and film. The digital proof, on the other hand, is done before film output and plate.

With developments in proofing rips, the digital proof has improved considerably; and it is often difficult to distinguish between the digital proof and the press proof.

Please take note that there are 2 kinds of digital proofs- the continuous tone proof and the post-rip dot proof. The dot proof has actual halftone dots. The ripped file of the dot proof is also used to produce the film or ctp plate.

Thats a good advice presstek. Here is mine, standardize your press soul2181. Those simulation profile or canned profiles in your proofer are print specification created from ISO 12647. But doing so is very expensive and worth doing it. If it is not possible to achieve on your press, least the closest as possible then customise your profiles.

I have already mark my calendar on sept. 29, 2pm. I am going to attain your lecture Presstek. I think this would be exciting.

Hi soul, here's what i do.

I have a digital printer. Before all this color management beast, i just used the proof i made on the digital printer, showed it to my client and gave it to production. Luckily, those jobs did not require a high amount of color consistency. And luckily, my operator was able to attain the desired output.

When clients are more particular about their job, i make a progressive proof still from the same digital printer. That way the operator can match the colors as they come out. Mind you i still dont have the measuring equipments. But i did my homework and at least try to "color mange" my devices. And I am not done yet...

ibler wrote:

Hi soul, here's what i do.

I have a digital printer. Before all this color management beast, i just used the proof i made on the digital printer, showed it to my client and gave it to production. Luckily, those jobs did not require a high amount of color consistency. And luckily, my operator was able to attain the desired output.

When clients are more particular about their job, i make a progressive proof still from the same digital printer. That way the operator can match the colors as they come out. Mind you i still dont have the measuring equipments. But i did my homework and at least try to "color mange" my devices. And I am not done yet...

Way to go!
Kuminsan kailangan lang gumamit ng Pinoy common-sense. Kung hindi tayo practical, walang mangyayari.
We sometimes have to make do with what we have.

Thanks presstech! I started doing that because i had my back against the wall already with that one particular client. Although the challenge was fun, it was also draining.

But since then i made it a point to work towards a full color-managed workflow. But it's just too damned tedious!!!

Thank you so much for all your responses, your recommendation have been a great help

Maraming Salamat Sir Presstech, Billy and Ibler!

ibler wrote:

When clients are more particular about their job, i make a progressive proof still from the same digital printer. That way the operator can match the colors as they come out. Mind you i still dont have the measuring equipments. But i did my homework and at least try to "color mange" my devices. And I am not done yet...

Ibler,

May I ask what application are you using in printing proofs? coz right now I only have Photoshop and Corel

Also, what kind of digital printer are you using? Is it inkjet or a digital coloured copier?

Soul, I use Adobe Photoshop and Adobe Illustrator. Sometimes Indesign. The Adobe Creative suite is very convenient because you only have to define the settings once. All other CS Apps will use the defined settings. That will make it easier to control and predict color output.

However, there are times that clients submit corel files. The color management of corel has improved tremendously so using it has no significant color issues. When I first started using corel, their management was way off that's why I tried learning the Adobe application. That plus the fact that Photoshop is the industry standard for image manipulation.

As for the proofer, I just use a digital laser printer. I experimented with it (and still continue to experiment) just so that I can control the idiosyncracies of the machine.

The bottom line is, whatever equipment you use, undertand its personality so you would be better able to control it.

The real solution to proofing problems is to install a proofing rip to the printer. The combination of a proofing rip with a good inkjet printer may require an investment of about P250,000; but it's worth the investment. This investment will give you the capability to produce proofs and progressives which accurately simulates the print that will be produced in the press run. This is important if you are printing a lot of full color jobs.

In my honest opinion, the proof is the center of color managing your press.

I agree with Billy, that you might want to standardize not only your press....but the whole prepress and printing process.

Are you using 1 icc profile on all application software?
ARe you using the correct rendering intent when printing your proofs (perceptual, saturation, relative col, absolute col)? etc...
Are your materials the same?

Standardization is one thing we usually overlook.

Once I tried fingerprinting our offset press......without standardizing the processes before it. BIG MISTAKE! It's like measuring something with a rubber ruler.

Another thing:
if your problem is color.....then check your icc profile or your proofer or press inks.

If your problem is lightness or darkness....check your dotgain.

If your problem is gray balance....check BOTH.

My thoughts only.

Standardization works FORWARD. Color Management works BACKWARD.
You miss one of these, you will be doing CIRCLES CHASING YOUR TAIL.

So where do we start?

from the proofer and work your way back to the monitors and the icc profiles and when that is done forward to standardize the prepress and the press?

This is always a chicken and egg question but really... where do we start?

ibler wrote:

So where do we start?

from the proofer and work your way back to the monitors and the icc profiles and when that is done forward to standardize the prepress and the press?

This is always a chicken and egg question but really... where do we start?

This is the question that a lot of fellow printers in our country encounter. Our printing industry is composed mainly of small and medium size companies with conventional or semi-digital prepress and second hand offset machines that are manually adjusted. When the company owner researches on how to apply color management, they are overwhelmed by the the amount of information that they encounter. They are eventually discouraged by the complexity of the system and the cost involved in applying it.

I used to own and manage a printshop; so I understand the predicament of the printshop owner. I started with a small Ryobi offset duplicator and nurtured the company until it attained medium size with four 2-color and one 1-color offset machines .

I suggest starting with standardizing the process step by step using methods that are practical and applicable to your particular setup. By standardization, I mean applying certain procedures in the process that will produce results which meet certain quality standards with regular consistency. This discussion will need a seminar; so I can only give some examples.

For example, you can standardize your plate making by using a sensitivity guide to establish the standard exposure time of your plate. This device costs only P450 and is very easy to use.

You can also improve the standard of your press by implementing the use of a color bar in your press runs. If you don't have a densitometer, you can use a color bar which is designed to be used with visual checking. Visual checking is not as accurate as checking with a densitometer; but it's a start. I have had this color bar used by some of my friends in the industry; and it has helped them improve the quality of their press runs. The great news is that it's free. Send me an email at philprinting@gmail.com and I will email you the files which you can attach to your layouts before film output.

There are so many thing to discuss regarding this matter. Next time I'll be in Cebu, we can probably meet .

Hi ibler. We can also begin our improvement efforts with our proofer. Some checklist, though:

PROOFING:

- Have we linearized our proofer? (if we have a RIP….then we have to)

- Are we using the correct ICC profile? Does the ICC correctly represent our printing process? IMO we can use ISOcoated_v2_eci.icc www.eci.org

- What is our Source profile.....and Destination profile? We can use ISOcoated_v2_eci.icc as our source, and use our printer profile (eg. LexmarkC90.icc) as our destination.

- Rendering Intent? If we're using the same press paper to print our proofs, then we can print our jobs using Relative Colorimetric. If we're NOT using the same paper..... we might as well print our jobs with Absolute Colorimetric..... so it will also include the color cast of our press sheet when printing our proofs.

- Did we turn off our printer driver's AUTO CORRECT or COLOR MANAGE features? We have to turn this OFF and let our application (Pshop) handle color management. Otherwise, we’ll have a case of double conversion.

To verify if our proofing process is according to the standards we can print the UGRA FOGRA Media Wedge.

If we don't have tools, then we can go to a shop that has. Have them measure our Wedge and compare our Actual Data with the Reference File (FOGRA39.txt). If our colors are all within Delta E of 5....our colors are okay. If our proofing dotgain for CMY is 53; and K is 56 then we're okay.

Gray balance, Color, and Tone accuracy, are just 3 of the many critical to quality (CTQ) parameters that one has to meet every time he has to make a proof.

If all three are thumbs up....then it means that our proofing process is accurately simulating ISO12647-2:2004.

If we're not meeting our CTQs, then we have to review our checklist and find out where we went wrong so we can correct it. At times, we may need to create another profile.

Whew! My humble thoughts.

Thank you very much sirs for the information!

Sir presstech, We made my own set of color bars. We've been using them for a couple of years now albeit inconsistently. I just followed the sequence of the colors from a color bar of a printshop here. I figured that it had some use even if we still don't have a densitometer. But the bars are there just not sure if i made them correctly.

We've been working on standardization. But this thing also needs work especially if the workforce is not very receptive to process changes. We're crawling but we're moving.

Sir larrysison, I have one computer to function as my proofing workstation. There is only one setting for the different applications so that i could somehow predict the output of the printer (that i use as a proofer). Although I have not mastered the other elements like rendering intents and source and destination profile, I have some idea on how they work and it helps me get the jobs right. So far, I'm contented with how i can control the machine. But there are just days when the machine acts up and everything is crazy.

But I'm not done yet experimenting. Maybe when we get the proper measuring equipments, I will be more precise with the calibrations.

BTW, somebody told me that the rip for my printer is not a good proofing rip. A friend who is using the same printer replaced the rip with a KPG. When they did, the colors were more consistent.

Again thanks!!!

KPG Proofpro produces clean black like serendipity black magic. It is a good SW RIP. Match it with a Kodak Paper and you're BINGO.