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  • Printing gradients with 2 Pantone colors

    Hi everyone,

    Its been years since I have worked in a pre-press environment, so my skills are a bit rusty to say the least. Here's the issue:

    We have a 2-color cover with a gradient goinf from Pantone 180 (red/orange) to Panton 116 (Yellow). I originally left this built in InDesign not knowing that banding was still an issue (as it is in Quark-built gradients). Our printer and their service bureau has so far offeen no solutions. So, how do I build a 2/color Pantone gradient that doesn't have any banding. I have been told this can be done in Photoshop, involving Spot Channels, but I am not experienced enough in this to know how to do it. Thanks.

    B

  • #2
    Re: Printing gradients with 2 Pantone colors

    B,

    First, you want to say that in many cases, going from one color to another makes the gradient look too light in the middle (where only 50% of each color is printing) to look good when printed. So in these times, you may want to print a gradient of the darker color over a solid of the lighter color. You want to try it both ways and soft-proof (turn on Overprint Preview and choose the output press ICC profile) to see which looks better. You can do this in InDesign or PhotoShop either one.

    Second, I wanted to say that I am a prepress person that uses Nexus, and haven't had problems in over five years with gradients. But some that use older equipment still may have problems with gradients. So here's the directions I would give for when the gradient needs to be rebuilt in Photoshop:

    You'll want to make a new CMYK PhotoShop document with the same dimensions width and height as your gradient in InDesign. Make it the resolution your service bureau uses in their rip (usually 300 unless specified otherwise by your service provider/printer).

    Note: I'm doing this in CS2.

    Go to Windows menu > Channels. Click on the arrow at the top of that Window. A flyout menu appears. Choose 'New Spot Channel...'. Another window opens. Click on the square to choose the spot color. Two icons under OK, if it says Color Libraries, that means you are in Picker and would have to click Color Libraries to choose a Spot color.
    I keep mine on PANTONE solid coated library in the pull-down list, unless choosing color for job printing on uncoated stock, which I would then choose solid uncoated library, or if choosing a Spot to print in CMYK, choose solid to process coated library. Type in 180 and it will go to PMS 180 in the list. Click OK. (Note: If you wanted your color to be a custom Spot color, you would choose the color to make it display here, and then OK.). Click OK again.

    Choose the PMS 180 channel (and make sure it's the only channel chosen), and do a gradation with the gradient tool, usually beginning at the far left of the document and going to the far right (or top to bottom, but always making sure that the foreground color is solid black and the background color is solid white, unless you want to go from a tint of one color to another). Now in channels window, drag the PMS 180 channel to the new channel icon at the bottom of that window to make a duplicate copy of PMS 180 channel. Double-click on that channel's icon, click the Color swatch, and type 116. Click OK. Click OK. Now go to Image menu > Adjustments > Invert. This will make an exact opposite gradation of the 180 channel.

    Now you see one scenario. I also want you to make another scenario where the PMS 116 is solid. Drag the PMS 116 channel down to new channel icon in channel window to duplicate it. Make sure solid black is chosen as foreground color. Edit menu > Fill... Foreground color, Normal, 100%, click OK.

    To soft-proof in PhotoShop: View menu > Proof Setup > Device to Simulate: choose an industry official ICC profile such as GRACoL2006_Coated1v2 if printing on coated, or choose ISO uncoated if printing on uncoated (or choose custom profile from your printer if you have one). Click Preserve CMYK Numbers. Check Simulate Paper and Simulate Ink (Click Save if you want to save the setup for easy choosing in the future). Click OK.

    You now have two PMS 116 channels. Turn them on and off to see which looks better with the PMS 116 channel. Delete the one you don't want to use, as well as deleting the CMYK channels, save as .psd, keeping the Spot Colors. place in Indesign at same X and Y location as InDesign-built gradation, and then delete InDesign-built gradation after making sure placed gradation is in correct position.

    The good thing about the solid, although it will change the other solid's color even if slightly, is that the gradation visually doesn't go too light in the middle. I use this almost technique always if I have a black gradation over a color. It just helps to make the black richer also, as well as fixing the "ghosted middle" look. If doing this technique in InDesign, you would simply:
    Duplicate (Step & Repeat at 0,0 offset) the gradation, make the top gradation from one PMS color to white, the bottom object solid, and then overprint the top object with the gradation.

    Hope this all helps.

    Don

    Comment


    • #3
      Re: Printing gradients with 2 Pantone colors

      Don,

      Wouldn't Illustrator do the trick as well; perhaps easier if you want shaped objects?

      Can one *safely* add noise to gradient spot channels in Photoshop? Now that might be a plus.

      inez

      Comment


      • #4
        Re: Printing gradients with 2 Pantone colors

        Inez, you are right. Of course, people have used adding noise to prevent banding in the past, and this would be done in Photoshop (some rips have it as an option also and do it on the fly - I have the option in my rip but haven't needed to use it). A small amount of noise can help especially if doing a gradation over 7 inches in length (I believe it was that I read), where the problems become more apparent because of very small percent of changes over longer distance (e.g. a gradient of 0-10% will of course band more than a gradient of 0-100% in the same distance. At some point the banding will become apparent especially if the rip is rounding percentages. Nexus doesn't round percentages and so the gradations are smoother IMO). Someone else will have to talk about noise settings perhaps, since I haven't had that particular problem in years, and my post focused on how to make the gradient in Photoshop. Thanks Inez for adding that info.

        Don

        Comment


        • #5
          Re: Printing gradients with 2 Pantone colors

          -To avoid the light "valley" in the transition area, rather than creating a gradient from PMS 116 to PMS 180, have it go from PMS116 to a combination of 100% PMS 180+100% PMS 116.

          To do this, first make a Mixed Ink that consists of 100% of both colors: Choose Mixed Ink swatch from the Swatches platte menu fly-out and check both spot colors and set the value to 100%.

          Then, create a gradient that's PMS 116 on one end and the new mixed ink on the other.

          This alone may cheer up your banding problem.

          -a PostScript Level 3 RIP shouldn't be having banding issues with this strong a gradient. Are you seeing this in inkjet proofs? It may be a linearization issue with that device. Or is this happening with final plate and print? Or is this job printing digitally?

          Comment


          • #6
            Re: Printing gradients with 2 Pantone colors

            As Claudia pointed out (maybe in a little different lingo), if the final printed piece looks like that, the plates may have curves that are not smooth, which would be the printer's responsibility to fix. As we see, there are multiple places for it to go wrong and band. Hope we have given enough info to help.

            Don

            Comment


            • #7
              Re: Printing gradients with 2 Pantone colors

              Hey, this is a great help. I thought I'd share some tricks I picked up, with doing gradients.

              One of the brands I work on has a thing for subtle background gradients. Their favorite background color is currently a soft blue, in the neighborhood of PMS5523. It's a very light color, I've included an image for reference.

              I found the easiest way to build a background file for this, is to build a CMYK gradient, in Photoshop. Instead of using the gradient tool, however, I place each color in a fill layer, using layer masks to build the gradient. Someitmes I build the color out of multiple layers of the same color.

              I then add noise to the layer masks (Filter > Noise > Add Noise), using a percentage between 1 and 5 percent, with Gaussian distribution. The percentage really depends on the size of the ramp, and the number of colors. It's something I play around with until the proofs look good.

              Comment


              • #8
                Re: Printing gradients with 2 Pantone colors

                Thank you all so much for your explanations. I now see how it should have been done and can be done. Much respect for you talents and knowledge.

                Comment


                • #9
                  Re: Printing gradients with 2 Pantone colors

                  After trying/soft-proofing the first 2 methods mentioned above, the second, involving the solid fill on the bottom channel appears much richer. The first method had the fading issue in the middle where they meet. I also did the mixed-ink method in InDesign. Excellent suggestion. I have yet to try some of the other ideas, but will just so they are in my mental library of tricks.

                  Claudia, to be honest I don't know what types of proofs these were, as they left the building last week along with the person who had that answer. I believe they were digital but other than that I don't have any more details. Since this job is off to be printed (and fixed at the printer) there isn't much I can do now. But, I will most certainly have a good handle on it for the next time. Thanks again to everyone.

                  Comment


                  • #10
                    Re: Printing gradients with 2 Pantone colors

                    OK, so I presented these concepts to the designers here so they are more knowledgeable and was presented a question I didn't know how to answer. When using the method Claudia mentions using the mixed inks in InDesign, what is actually going to happen when it goes to print. The designer here was under the impression that this would create and actual mixture of the 2 inks when printed. I imagine this is taken care of on the RIP side of things involving overprinting where the mixed ink is interpreted a certain way by the RIP. Any quick explanation would be appreciated.

                    Comment


                    • #11
                      Re: Printing gradients with 2 Pantone colors

                      You're welcome Benton. I learned something from this too. Although I knew Quark had multi-ink option in the Swatch palette, I didn't know InDesign did as well. Learn something new everyday.

                      Don

                      Comment


                      • #12
                        Re: Printing gradients with 2 Pantone colors

                        Benton,

                        I just did a test and sent the multi-ink InDesign doc to my rip, and also saved as PDF/X-1a and dropped on a hotfolder to my rip. Just as you see in InDesign with Separation Preview is how it ripped - the yellow is solid and the red gradation overprints it.

                        Don

                        Comment


                        • #13
                          Re: Printing gradients with 2 Pantone colors

                          The designer here (who likes to play devil's advocate—to put it politely) argues that the mixed ink swatch and overprinting the orange will cause it to not look like it would were it not mixed/overprinted. Will the orange (defined as a mixed ink swatch of 100% of the 180 and 116) overprinting the yellow (116) still closely match the 180 in the swatch book? This will be my last question on this issue as I know everyone is busy. Thanks again.

                          Comment


                          • #14
                            Re: Printing gradients with 2 Pantone colors

                            Benton,

                            As said before the first time I replied:
                            "The good thing about the solid, although it will change the other solid's color even if slightly, is that the gradation visually doesn't go too light in the middle. I use this almost technique always if I have a black gradation over a color. It just helps to make the black richer also, as well as fixing the "ghosted middle" look."

                            It may not match PMS 180 but will be a darker (IMO better) red.

                            Having said that, if you must match 100% PMS 180 on one end (or as close as possible), you may want to build it in InDesign and have a swatch of 100% PMS 180 at the PMS 180 end of the gradation, and build a mixture of a screen of 180 and solid PMS 116 until you get as close to the actual appearance of 180 as possible. What do you think about that Claudia? Or would it be better to just let it be 100 over 100?

                            Don

                            Comment


                            • #15
                              Re: Printing gradients with 2 Pantone colors

                              Well, since Claudia hasn't replied, you really have two choices:
                              1. Use noise to help banding problem.
                              2. Use the technique of gradient of one ink over the other ink solid.

                              With number 2, realize that even at the 180 side of the gradation that there is some of the other ink mixed in (since it is a gradient), and know that none of the gradient looks like PMS 180. Unless the PMS 180 end of the gradation is touching a solid PMS 180, then no one will likely know that the two are made up of two inks, and will just think it's a mighty nice gradation. Also note, that unless you have the "ghosting" problem in the middle of the gradation, then you won't need to use #2 option. Maybe I was wrong in posting it, since in this situation, yes option #1 is probably better.

                              Don

                              Comment

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