Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: r010159 on August 29, 2015, 09:20:13 pm

Title: What causes banding on a print?
Post by: r010159 on August 29, 2015, 09:20:13 pm

I have been profiling a RIP for a CMYK profile. When I print using the RIP with its new profile, I notice subtle banding on the grey ramp. What can be causing this? The printer profile? Perhaps a more careful choice of target patches would help? A limitation of the printer? A RIP set up improperly? For that matter, how about RIP independent reasons? I am interested in understanding this phenomenon.

Thanks!

Bob

Title: Re: What causes banding on a print?
Post by: Jeff-Grant on August 29, 2015, 10:46:36 pm

On an Epson printer, I would expect clogged nozzles. What printer are you using? Is the banding over the full print?

Title: Re: What causes banding on a print?
Post by: r010159 on August 29, 2015, 11:01:16 pm

I have created a CMYK profile for my RIP. I had printed a standard printer test photo which includes a grey ramp. This is where I found subtle banding with the grey ramp. Between this and a green tint to the ramp. I am unable to use this profile. I have followed instruction for creating the profile per the RIP's manual. I am using an Epson 3880 with the PrintFab RIP.

Bob

Title: Re: What causes banding on a print?
Post by: Jeff-Grant on August 30, 2015, 02:37:13 am

Do you get a good nozzle check? Clogged nozzles is the most common cause of banding.

Title: Re: What causes banding on a print?
Post by: r010159 on August 30, 2015, 03:10:29 am

My nozzle check is fine.  I do not get this from the RGB OEM profile which. by the way, reproduces the grey ramp as neutral.

Title: Re: What causes banding on a print?
Post by: Jeff-Grant on August 30, 2015, 03:21:54 am

That's really odd. I've worked with a few RIPs and never seen anything like that, sorry.

Title: Re: What causes banding on a print?
Post by: GWGill on August 30, 2015, 09:58:47 pm

Quote from: r010159 on August 30, 2015, 03:10:29 am

My nozzle check is fine.  I do not get this from the RGB OEM profile which. by the way, reproduces the grey ramp as neutral.

Note that the black curve can make a great deal of difference to how obvious banding is. 100% GCR will make it most obvious, whereas a GCR that has a small amount of black will cover it up more effectively, but will have a less robust neutrals. This could be the difference between your profile and the OEM RGB workflow.

Title: Re: What causes banding on a print?
Post by: r010159 on August 31, 2015, 11:05:18 pm

Thank you for your very informative reply! I have so much to learn about GCR Mode, GCR Amount, Black Start, Black Width, TAC and so forth. I still have not figured out Black Start and Black Width...width of what?? Oh well, I will eventually learn this. :)

Bob

Title: Re: What causes banding on a print?
Post by: GWGill on September 01, 2015, 03:59:54 am

Quote from: r010159 on August 31, 2015, 11:05:18 pm

I still have not figured out Black Start and Black Width...width of what??

I would imagine that "width" controls how far from the neutral axis the GCR extends. Narrow = UCR, Wide = GCR.

Title: Re: What causes banding on a print?
Post by: BobShaw on September 06, 2015, 07:00:19 pm

Are you printing 8 bit? If so print 16 bit.

Title: Re: What causes banding on a print?
Post by: r010159 on September 07, 2015, 09:29:49 pm

OK. I will try that. Thanks.