Gradients show banding in illustrator - please help! - Adobe illustrator

This is a discussion on Gradients show banding in illustrator - please help! - Adobe illustrator ; I have searched these forums and haven't yet found a comment that works, I am producing a folder that has alot of gradients that show up in illustrator and makes the design look ugly. I have tried playing with the ...

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Gradients show banding in illustrator - please help!

  1. Default Gradients show banding in illustrator - please help!

    I have searched these forums and haven't yet found a comment that works, I am producing a folder that has alot of gradients that show up in illustrator and makes the design look ugly. I have tried playing with the DPI and LPI but the banding is still there. I am trying to create a PDF to send to the printers and don't yet know how to get rid the banding, and not sure if its the LPI etc...

    We are using Mac OS X 10.4.4, 2 GHZ intel Core Duo, 1.5 GB DDR2 SDRAM. Ill CS2...

    The file (unfinished) is at <http://www.egocreative.com.au/kenpar_folder.pdf> Your help would be greatly appreciated

    im not sure what other info I can give that may help, basically I would like it to blend nicely wihout the dark 'steps' and know there must be an easy way to overcome this prob.

    Thanks in advance

  2. Default Re: Gradients show banding in illustrator - please help!

    im 99% sure the 'banding' is a screen only thing.
    but on that PDF i didn't actually notice any banding (viewing in Acrobat 5.0). if i zoomed in by 750% i saw some banding.

    once printed on a litho press it will look fine. but i would express your concerns to your printer before you send to print, just to be sure.

    use quite a lot of gradients and never have had banding on a finished piece. though i have noticed that when viewing such bits of work that are on my website you can see banding when viewed on a 17" mac powerbook. but on my ancient 21" Formac monitor i don't see ANY banding. go figure...!

    good luck!

  3. Default Re: Gradients show banding in illustrator - please help!

    Thanks for your comment Typo man, i'll try viewing it on other computers to see if its the same... im not sure how to change the screen so it gets rid of it ( if I can though)

  4. Default Re: Gradients show banding in illustrator - please help!

    It is not a screen issue. It has to do with the percentage of color you are stating and ending at. The are only 256 levels of gray. A gradient is made up of "steps" of gray. Every .39% there will be a step. It looks like you have a very slight gradation in your folder. Your folder is approximately 15" tall. If your use 20% of a pms to 10% of a pms you will only have 25 steps to complete your gradient in that distance. Every .6" you will see this. Gradients are just like resolution the more steps you have the less you notice it.
    Options are
    A. Increase the starting point and lower the ending point 100% to 0% with a lighter pms
    B. Make the gradients smaller
    C. Open them in photoshop and apply a blur to them.

  5. Default Re: Gradients show banding in illustrator - please help!

    "Open them in photoshop and apply a blur to them."

    That won't work. Adding noise will fix banding.

  6. Default Re: Gradients show banding in illustrator - please help!

    I examined the file and I believe this is in fact a screen only issue. You have a CMYK gradient, and when viewed within Acrobat, it displays each channel using 8 bits of precision. Because of the specific colors chosen, each ink channel ramps a little differently. They are all changing by the minimum possible at each step, but for each ink channel, the steps are in different places. Occasionally, the steps will coincide...for example a minimum change in cyan ink density plus a minimum change in black ink density will look more obvious than a minimum change in just one of the channels.

    If you send this file, containing gradients, to the printer, then that gives the printer a chance to interpret the gradients in a manner most favorable to the print process. Of course, the RIP may do it a cheaper way and show the banding. I cannot tell you if the print will have bands or not. I can say that just because there are bands on the screen, it does not mean there WILL be bands on the printout.

    So, what I see is an aspect of your screen display. Some printers will NOT show the banding but some will; depends upon how sophisticated the RIP software is on the printer.

    And, if you want to eliminate this banding on the screen, you can add in a very slight amount of noise. But introducing noise to fix banding on the screen could easily introduce an undesirable grainy noisy texture to your printout.

  7. Default Re: Gradients show banding in illustrator - please help!

    There is a point regarding screen resolution. Is your monitor setup to display millions of colors or only 256? Are you viewing on a small 640x800? If so, then banding will occur on the monitor ( +1152x840 is better ). The file itself may have a low document resolution ( perhaps set at a default of 800dpi output res ). All of these variables can create banding either on screen or upon output or both. Confirm your document's output resolution is set at 2540dpi and the Gradient Mesh resolution is set at 300ppi. You usually do not encounter LPi until you get to the RIP.

    I viewed the file on my monitor @ 1600x1200 @ millions of colors and saw no banding. So, my guess is your monitor's resolution is set too low, along with colors displayed. Use my recommendations above and you should be OK.

  8. Default Re: Gradients show banding in illustrator - please help!

    I definitely see it at 1280x1024.

  9. Default Re: Gradients show banding in illustrator - please help!

    My monitor settings are at 1680x1050, millions of colours... I am still working through it and going by what Chris Rodkey mentioned at the moment. The gradient is still showing banding though at this stage. Though I am very greatful for your suggestions I am thinking that it may be either the printer or something to do with my display. Still working through it so thanks for all your help so far, hope to get a fix soonish.

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