basic idea of including a controlstrip in a print?

[sharath.1628]

Hi Guys,


Can somebody let me know what is the basic idea of including a controlstrip in a print?

(By controlstrips i mean the patches that are used for color management and not any other quality targets.)

Is it to check whether the printer prints these patches correctly?

or to check how these patches are printed when a profile is applied to the image with which the controlstrip is included and printed.

Any answers would be greatly helpful.

 

[Devildogdan]

Color Strips

Color Strips

The color strip in basic form is for the Pressman to run to density on Press, and to check for slurring and register as well. These strips are measured with a colormeter or scanning denisitometer or a spectrophotometer. Depending on the application of course. It's sounds as though you are just venturing into color management. Good luck...
There are more advanced strips used for Press profiling.

 

[sharath.1628]

basic idea of including a controlstrip

basic idea of including a controlstrip

Thanks for the reply.

Have you worked with conrolstrips and measured delta E values.

My question is does the profile that we use for the image affect the control strip.

Because the controlstrip that we use usaully is in CMYK color space. What happens if we print a RGB job with a RGB source profile and print the job along with a controlstrip.

Any idea of whether the RGB profile affects the controlstrip?

 

[Lukas Engqvist]

Usually the control strip controls... but the question you ask is what, and that depends on where you apply the control strip. If you use a media wedge (like FOGRA) it is usually a check of the CMYK process, and in my opinion should go through the same process as other CMYK data. It will tell you if you are printing according to standard, and is useful for comparing TVI and grey balance, and getting objective comparison between proof and printed sheet. It is a little like taking the temperature to see if you have a fever.

IF you convert the strip to RGB you can test that your RGB work flow is as you expect. The control strip can also be converted to LAB. So it can be used in different ways, and is a quick help to see that you get what you expect to get. If you get a "proof" from your client, you can use the strip to verify that the proof is reliable, or to put numbers on the deficiencies of the proof (when comparing to your own proof).
Hope that explains more than it confuses.

 

[sharath.1628]

Question

Question

Thanks Lukas,

I think im confusing you guys.

Let me state the scenario.

CMYK JOB:
I print the job and measure the controlstrip and the deltaE values are within the Tolerance. Fine. Here both the job and the controlstrip gets the CMYK profile applied.

Now my question is concerning when we use RGB JOB:
When we use a RGB job is it right procedure to use the RGB profile for the controlstrip or to use the CMYK profile and measure and check whether the printer is printing correctly.

Are we testing how the profile affects the job or whether the printer is correctly printing a controlstrip when we are use a controlstrip.

Hope this makes it clear

 

[michaelejahn]

Clear as mud

Clear as mud

Now my question is concerning when we use RGB JOB:
When we use a RGB job is it right procedure to use the RGB profile for the controlstrip or to use the CMYK profile and measure and check whether the printer is printing correctly.

Are we testing how the profile affects the job or whether the printer is correctly printing a controlstrip when we are use a controlstrip.

Hope this makes it clear

Control strips can be used in several ways. Many would argue that you should NEVER apply a profile to the control strip, that it should ALWAYS be CMYK (and perhaps contain items related to any spots you might be using. This would then be considered a printing process control type of approach. We are a reseller of pressSIGN, and most of our customers use it in that manner.

Now, what you seem to be thinking about is some RGB colorbar - where you are using this more as a 'what is my workflow / profiles / color management / plate curves / ink optimization process doing to the RGB images from PDF to Plate - that is entirely a different type of colorbar.

download and read the contents of this poster;

DEER Printing Guidelines 2011 Poster-DOWNLOAD | IDEAlliance

If you are interested - we can help - email us at [email protected]

 

[Gaurav Vidwans]

basic idea of including a controlstrip

basic idea of including a controlstrip

The basic idea behind including a colourstrip in a print is to check the density of the ink. If you look at the color strip in detail it is designed in a such way that each ink duct key will have at least one colour patch of each colour being printed( i am talking about offset - sheet / web fed)

Thus the operator can measure the density of ink for each ink duct key and then can adjust the flow of the ink or adjust the emulsification.

We never applied any profile to the colourstrip as our main aim was to check the ink density (Actually there was no need to apply any profile as all were solid patches in the colour strip)

The aim of the colour strip in our case was only to check whether the machine is printing right density of the ink

 

[TerryWyse]

Hi Guys,


Can somebody let me know what is the basic idea of including a controlstrip in a print?

(By controlstrips i mean the patches that are used for color management and not any other quality targets.)

Is it to check whether the printer prints these patches correctly?

or to check how these patches are printed when a profile is applied to the image with which the controlstrip is included and printed.

Any answers would be greatly helpful.

I assume you mean control strips (or color bars) on a proof.

They can be used generally in 1 of 2 ways....

1) They can be used to verify or "certify" a proof to a standard specification such as GRACoL or SWOP.
In this case, you would print/proof the control bar with color management on using the relevant print specification and then measure/compare the control bar against the L*a*b* values for that standard. The IDEAlliance 12647-7 control strip is a good example of this. Besides the CMYK values in the control strip, they also include reference L*a*b* values for each of the patches for each of the standard specifications.

2) The 2nd method is simply for quality control of the proof itself...that is, to verify that the proof isn't "drifiting" irrespective of any standard printing condition.
In this case, the control strip is not compared to standard printing condition such as GRACoL/SWOP but to reference values from the proofing system itself when it was (presumably) freshly calibrated and/or profiled.
What you do in this case is that immediately after calibrating/profiling the printer and are satisified that all is well, you print the control strip, measure it and then store these L*a*b* values as a reference of this printer in optimal conditions. The control strip in this case could be printed with EITHER color management ON or OFF. If it's printed with color management on, it needs to be noted as such. I would suggest that if it's *primarily* for checking whether the printer is in control, then you should print the control strip UN-color managed since with color management enabled, it will tend to hide the fact that the printer may in fact be drifting at the outer edges of the printer's full gamut.

Terry

 

[sharath.1628]

Thanks

Thanks

Hi All,

Thanks for the clarifications. It was really helpful.

 

[BeauchampT]

If you are really trying to colour manage, it would be best to standardize your entire workflow. Even if you are getting jobs from clients in RGB format, convert it! Make your own proof and show them what they can actually expect to get. The whole concept of colour management is to be able to actually predict what you are going to get as a final product, not what a graphic designer was hoping it would look like. The benefits to converting will also help your press operators, since they won't ever have to be guessing at what system they are trying to follow.

Just a thought