2 Replies Latest reply on Jul 11, 2013 12:02 PM by Mylenium

    How to make drop shadows without banding for offset printing?

    mc_mark Level 1

      I like to make drop shadows under our products on our brochures. While they look great on screen, they suffer from banding on the printed pieces via offset printing. Here's how I make them now in CS6:

       

      1. Create a layer under the main image.
      2. On this layer use Rectangle Marquee tool to create box in location of desired shadow.
      3. Hit Shift + F5 and Fill with Black.
      4. Deselect the black filled box.
      5. Go to Filter > Blur > Gaussian Blur and select a radius of 40-80 depending on the size of the image.
      6. Go to Filter > Blur > Motion Blur and select a distance of 125 -250 depending on the size of the image. Also select appropriate angle to match image.

       

      I've talked to my printer and they said this is fine but they also said to make sure I'm filling the box with only K and not RGB (which I am) and to adjust opacity so it's below 25%. The problem is when I set the opacity of the shadow layer to 25%, the shadows are barely visible. This is not what I want. I want a nice dark shadow under the main portion of the product and the fading out to nothing. The way I do it now looks great on screen so how do I get it to look great on paper?

        • 1. Re: How to make drop shadows without banding for offset printing?
          Mylenium Most Valuable Participant

          Blindly advising to set shadows to 25%? I'm not sure whether this makes me laugh or weep. It's really missing the point completely. As long as your shadows are properly visible in the CMYK channels and don't exceed the maximum ink density, they will print properly. It's not like black would be printed on top of all other colors in offset printing, you know. It gets halftoned just like the other inks. Similarly, your banding problems come down to understanding this part - banding occurs if the color is too dense and it results in too large/ to dense halftone dots produced where they shouldn't or on the other hand the printer oversaturating colors and exceeding the maximum color a dot can take, so there's a lot of dot gain due to the ink seeping out. There may of course be limitations like e.g. your shadows only achieving the correct densities when reducing their opacity, but 25% is like telling van Gogh he should have painted those sunflowers pink...

           

          Mylenium

          • 2. Re: How to make drop shadows without banding for offset printing?
            Mylenium Most Valuable Participant

            And BTW to diagnose such issues it always helps to have screenshots of the artwork and proper technical info like ducument sizes and resolution...

             

            Mylenium