vignette problem image 2

[kala]

Pls find attached image 2 shows banding problem @ printing ...

Tried regenerate in photshop / illustrator / corel no improvement..

can any expert help to sort out this issue pls..

regards
kala

 

[PPT25]

there is NO indication of banding in the jpeg you posted! what program was the image created in?
when we have this problem--we open the image in photoshop and add a small amount of 'noise' and then output to our epson proofer to see if the banding goes away--IF the image is a spot color--the problem can be solved by changing the output (plate) screen angle--IF CMYK try adding 'noise'
IF original is an illustrator file--try rasterizing the image--either way if you can only output to plate, you won't see the banding until output

 

[DCurry]

I can see the banding.

I second the "add noise" idea, with the added step of making sure you only add noise to the C and Y channels since there are no pixels on M or K you don't want to introduce them. You can probably go heavier on the noise in the Y channel. Make sure you choose "Gaussian", not "Uniform" in the Noise options.

Saving this image as JPEG is not helping, either. I can see some JPEG artifacting when I look at the individual channels.

I've always found that gradients and blends created in programs other than Photoshop and then rasterized still tend to show banding more than if the gradient is created from scratch in Photoshop. Not sure why that is.

 

[LSW]

What is the printing process?

 

[gordo]

--IF the image is a spot color--the problem can be solved by changing the output (plate) screen angle--

Could you explain why or how that would work?

Gordo

 

[PPT25]

Could you explain why or how that would work?

Gordo

---there are variables--but--assuming a direct to plate process is being used--by default most platesetters use a 15 degree screen angle for spot plates--change it to 45 or 90 and the banding 'may' disappear

 

[gordo]

---there are variables--but--assuming a direct to plate process is being used--by default most platesetters use a 15 degree screen angle for spot plates--change it to 45 or 90 and the banding 'may' disappear

I don't know of any mechanism or way that a screen angle can affect "banding."

Best, gordo

 

[kala]

Tried by adding spatter / brush strokes to the gradient and supplied the plates to the print house and awating for the results..

 

[Repro_Pro]

Could the term "banding" actually refer to Moire?

Assuming the gradient is printed in Process inks, I would try exchanging the angles of the Yellow and Black printers.

Good hunting!

 

[topdot]

Pls find attached image 2 shows banding problem @ printing ...

Tried regenerate in photshop / illustrator / corel no improvement..

can any expert help to sort out this issue pls..

regards
kala

Hello Kala,

This issue is typically due to color calibration curve that is not very smooth. Quite often, if you use too many nodes in a tone calibration curve (for example between 5% increments) it becomes difficult to maintain a smooth curve that renders vignettes that show a gradual change between percentages. You can test this by temporarily de-activating the curve being applied to this color and observe the results. If you prove that the curve is causing the problem, then the solution is to reduce the number of nodes to about 5 or 7, carefully maintaining the same shape of the curve you are using.

 

[kala]

Problem solved by adding little bit spatter brush strokes.. FYI