19 Replies Latest reply on Aug 26, 2009 7:18 AM by Steve Fairbairn

    Overprinting gradient fills

    RJStalker Level 1

      I'm trying to create a gradient fill in which I have three spot colors.  The top two overprint.  I can set it up perfect in the appearance dialog box, but when I try to apply gradients to objects I can only adjust one gradient at a time.  It's nearly impossible to adjust all three colors to line up perfect using the gradient tool.  Is there a way that I can use the gradient tool to position all three gradient fills at once?

       

      In a related issue, is there a way to emulate opaque or semi opaque spot colors such as white in illustrator when using overprint preview?

       

      Thanks.

        • 1. Re: Overprinting gradient fills
          Wade_Zimmerman Level 6

          In the attributes panel you can set the fill to overprint.

           

          But perhaps you want to make a compound path and use one gradient with the tree colors as one gradient.

           

          And if you have CS 4 you can give the gradient color any amount of transparency you want or make it opaque.

           

          Like this

           

          Picture 7.png

          • 2. Re: Overprinting gradient fills
            RJStalker Level 1

            Now let's say you want to be like this:

             

            Location: 0%

            0% blue

            0% orange

             

            Location: 50%

            100% blue

            0% orange

             

            Location 100%

            100% blue

            100% orange

             

            With spot colors you can't assign 100% of both spot colors at one location.  You have to do two fills in the appearance panel.  But if I want to use the gradient tool to assign the location and direction I can only do one at a time.  Then I'd have to estimate the location or copy an object for every fill with all of them over printing, except the bottom.  It's an illustration so I have a lot of objects, and many have 3 spot colors, so I'd have 3 times the objects on an already heavy file.

            1 person found this helpful
            • 3. Re: Overprinting gradient fills
              JETalmage Level 6

              One object, two fills:

               

               

              No, Illustrator's Overprint Preview does not take into consideration the opacity of ink. And Illustrator does not provide for mixing spot inks in one swatch. (Both very longtime complaints.) So if a file containing opaque inks is built properly for printing (very common in screen printing) Overprint Preview does not help. That's one reason why, beyond very simple designs, it's less tedious, more intuitive, and less limiting to build such projects in Photoshop as a multi-spot-channel image.

               

              JET

              2 people found this helpful
              • 4. Re: Overprinting gradient fills
                RJStalker Level 1

                Thanks.  I've even looked for plug-ins that could fix this limitation.  It seems incredibly short-sighted to limit over printing gradients like this. hopefully the next release fixes this.

                • 5. Re: Overprinting gradient fills
                  Steve Fairbairn Level 5

                  Illustrator does not provide for mixing spot inks in one swatch.

                  Yes it does. You can make a gradient of 2 or more spot colours and (as long as you don't expand it) the gradient will separate into as many plates as there are spot colours. Overprinting spots  and spot gradients works o.k. too. Take a peep at the output preview of such a pdf-compatible file in Acrobat if you're not convinced.

                  I'm not quite sure how transparency stops affect things - haven't moved on to CS4 yet.

                  Steve.

                  • 6. Re: Overprinting gradient fills
                    JETalmage Level 6
                    Yes it does. You can make a gradient of 2 or more spot colours and (as long as you don't expand it) the gradient will separate into as many plates as there are spot colours. Overprinting spots  and spot gradients works o.k. too. Take a peep at the output preview of such a pdf-compatible file in Acrobat if you're not convinced.

                    Steve,

                     

                    I am well aware of the ability to use spot colors in grads. (Would that Illustrator similarly supported the same in Blends, as have other programs long before it).

                     

                    But I said nothing about spot colors in grads. I said Illustrator cannot combine multiple spot colors as components in a single Swatch (as can other programs long before it, including Adobe's own InDesign).

                     

                    Read the earlier posts in this thread; specifically the mention of the specific color example. You can have multiple spot colors in a grad; but you cannot have 100% of two spot colors at one end (one color stop) of that grad. (Thus the need to resort to multiple fills and overprinting.)

                     

                    JET

                    • 7. Re: Overprinting gradient fills
                      Printer_Rick Level 4

                      RJStalker wrote:

                       

                      With spot colors you can't assign 100% of both spot colors at one location.  You have to do two fills in the appearance panel.  But if I want to use the gradient tool to assign the location and direction I can only do one at a time.  Then I'd have to estimate the location or copy an object for every fill with all of them over printing, except the bottom.  It's an illustration so I have a lot of objects, and many have 3 spot colors, so I'd have 3 times the objects on an already heavy file.

                      It is true that you can't edit 2 or 3 separate gradients simultaneously. But you can:

                       

                      1. Duplicate the gradient fill in the appearance panel, then change the colors.

                       

                      2. Once you have the total appearance defined (multiple gradients applied to one object) - in the graphic styles panel, New Graphic style

                       

                      3. Apply the graphic style to objects

                       

                      4. Need to tweak the graphic style later? No problem. Deselect all artwork. Select the graphic style. In appearance panel, modify the appearance. Then "Redefine Graphic Style"

                       

                      Another suggestion - darken blend mode is similar (emphasis on similar) to overprint. For PDF viewing purposes sometimes transparency is preferable to overprint, darken is the most like overprint (although not exactly the same in all cases)

                       

                      And no AI has no equivalent to the spot channel solidity setting in Photoshop. Not yet anyway...

                      • 8. Re: Overprinting gradient fills
                        Steve Fairbairn Level 5

                        Sorry, I thought (obviously perhaps) that you were talking about spot gradient swatches. It's all a question of terminology.

                        What you are fishing for is to be able to produce multiple spot channels from a single swatch.

                        O.k., you can do it with up to four process colours C+M+Y+K, so why not spot colours too? And why not a mixture of spot and process for that matter? Sounds reasonable when you come to think of it.

                         

                        Seems like Illie (I believe she's officially female now!) has now hit some of the same channel mixing output problems as Photoshop, at least as far as swatches are concerned. We have long been able to overprint and multiply spots and CMYKs together in Illie but not make swatches of a mixture of channels other than CMYK.

                         

                        You say that spot channels can be combined into a single swatch in InDesign. How? Does an object coloured with it separate properly into its component spot channels? Can you mix process and spot into a single swatch? Can you copy such a swatch (or a coloured object made from one) from InDesign into Illie? If so, how does it separate?

                         

                        This is all news to me and sounds exciting. What we need is a fully functional multi-channel environment in Illie and Photoshop. As you know, Photoshop doesn't currently support multi-channels except in a very crude fashion - you can't work in multi-channel and layers simultaneously. I haven't the faintest idea why not and have been complaining about the problem for years. Reckon it's long overdue for Adobe to completely re-think their colour channel management. When it comes to the crunch there's no difference between a process channel and a spot channel - each produces its separation plate - so of course we should be able to add and subtract channels as required. Just imagine having countless sliders in your colour palette allowing for any mixture of channels, spot or process. Every time you add a spot colour it gets added to the CMYK slider list allowing you to make a mixture of any channels you choose. Chuck out maybe cyan and it disappears fron the list. The mind boggles .

                        • 9. Re: Overprinting gradient fills
                          Printer_Rick Level 4

                          ID supports DeviceN color and the other Adobe apps do not

                           

                          (But then ID does not have grayscale either...)

                           

                          DeviceN first surfaced in Quark a long time ago. A one channel tiff was actually a two channel image. It happened by redefining White or Paper (referred to as background in Photoshop)

                           

                          With vector swatches using DeviceN, an ink can be defined as 0 - 100... or TRANS. The trans is like punching a hole through the separation to allow the other colors to show through.

                           

                          Basically a mask...

                           

                          DeviceN in InDesign is seen in Multi-Ink, but also exists in colorized grayscale images.

                           

                          The color space is all over InDesign PDFs. Illustrator now recognizes DeviceN images but you can't really edit them.

                           

                          In order to edit the images in Photoshop they need to be split into a normal image with an alpha channel. Some PDF editors (Neo) can do this. If you try to open the images from Acrobat you get the unsupported color space message.

                           

                          Just output a grayscale image from InDesign, try to open from Acrobat you'll see the message.

                           

                          If you create a mixed ink in InDesign, output PDF and try to open in Illy you get "unknown imaging construct encountered"

                           

                          A long time ago Quark created an image editing program called X Posure that supported Device N but the app fell by the wayside. It is amazing that still today Illy and Photoshop cannot really handle this color space. Hopefully soon they will.

                          • 10. Re: Overprinting gradient fills
                            Printer_Rick Level 4

                            steve fairbairn wrote:

                             

                            When it comes to the crunch there's no difference between a process channel and a spot channel - each produces its separation plate - so of course we should be able to add and subtract channels as required. Just imagine having countless sliders in your colour palette allowing for any mixture of channels, spot or process. Every time you add a spot colour it gets added to the CMYK slider list allowing you to make a mixture of any channels you choose. Chuck out maybe cyan and it disappears fron the list. The mind boggles .

                            This is good to think, but a nightmare to incorporate into color management. I think that's the road block.

                             

                            Imagine if someone had an RGB image. And they could go Mode: DeviceN: And choose 17 different Pantones to build their image.

                             

                            Very difficult to engineer.

                             

                            (Edit: this can be done with Photoshop plug-ins but the end result is not a Device N color state, it's always stacked spot channels)

                             

                            Then the inks have to participate in layers, and you have a DeviceN composite channel. But with 17 inks, layer blend modes become extremely complex very fast.

                             

                            It's nice to think about but I imagine Adobe would have to rebuild Photoshop. The vector side is a little different, that may be more attainable. But right now in Illustrator, RGB and CMYK can't coexist (not really). So throwing DeviceN into the mix may be a tall order...

                             

                            Message was edited by: Printer_Rick

                            • 11. Re: Overprinting gradient fills
                              Steve Fairbairn Level 5

                              Yep, I realize that it would involve some rethinking. And you note that I deliberately didn't mention RGB because that's a completely different kettle of fish, based on additive mixing. A multi-channel slider setup would only be useful for print output. But it would nevertheless be extremely useful.

                              Presumably colour conversion from RGB to process would have to start off as ordinary CMYK with the option to add channels afterwards.

                              I am not familiar with the term "Device N mode" – can anyone elaborate please?

                              And I still don't understand why Photoshop still limits us to flat multi-channel files. What is the problem with adding channels to layers (or as layers)? The present arrangement is very cumbersome, time-consuming and limiting.

                              • 12. Re: Overprinting gradient fills
                                Wade_Zimmerman Level 6

                                DeviceN is a method that allows the color to be specified is Device 

                                independent and can go outside the normal Color Gamuts of rgb and cmyk.

                                 

                                Whether or not the device supports it that is outside of the process, 

                                such as a spot color. Or in this case a spot color.

                                 

                                http://www.adobe.com/devnet/postscript/pdfs/TN5604.DeviceN_Color.pdf

                                 

                                The above PDF explains in it in detail the support is there in AI CS 4 

                                more complete than it is in CS 3 and I believe it was introduce to Ai 

                                in CS 2 or perhaps in CS  but not as consistent.

                                 

                                Tha means you can have spot colors in gradients the color can under 

                                stood by the Postscript driver regardless of if the Device understands 

                                it.

                                 

                                It differs from HiFi color but from the article is related to it in 

                                that they both increase the gamut and and go beyond the normal device 

                                support but with Hi Fi you need a device that supports it, with the 

                                DeviceN color mode the langauage will properly separate the to the 

                                specified colors, that is it knows which colors are not a part of the 

                                rgb or cmyk color space and properly separates them accordingly. The 

                                Device will produce a separate output for the colors and it will be 

                                differnt from th rgb or cmyk components.

                                 

                                That is the ay I see it at least.

                                • 13. Re: Overprinting gradient fills
                                  Steve Fairbairn Level 5

                                  Thanks, Wade.

                                  I took a quick look at the pdf and will "wade" through it better when I have a mo .

                                  Looks promising – like like the Adobe guys are at last beginning to re-think things.

                                  Seems to me that a simple method of combining spot and process channels is long overdue.

                                  The huge problems with working with multi-channel in Photoshop has been bugging me for years, so maybe it won't be long now.

                                  Steve.

                                  • 14. Re: Overprinting gradient fills
                                    Wade_Zimmerman Level 6

                                    I am sot of with you I would like to work with the channels in both PS 

                                    and Ai as color components not necessarily layers but would love a way 

                                    of looking at the color component and be able to see where in the 

                                    document structure the colors are by opening the component is such a 

                                    way as to see on what layer the component resides and what form it 

                                    takes on the location.

                                     

                                    For instance say it is a Letter T and it resides on a sublayer of 

                                    Layer 1 I would like to be able to expand the color component say in 

                                    this case a spot color and see it listed there with a preview of the T 

                                    now I know I have the T properly assigned to the letter T and not one 

                                    or more of the cmyk components.

                                     

                                    Does this make sense?

                                    • 15. Re: Overprinting gradient fills
                                      Printer_Rick Level 4

                                      steve fairbairn wrote:

                                       

                                      I am not familiar with the term "Device N mode" – can anyone elaborate please?

                                      Don't feel alone. Nobody really understands it. Sometimes I think I do but I don't really.

                                       

                                      Device N is simply weird.

                                       

                                      As far as images, best way to see it is with InDesign. Place a grayscale image (one with a background layer). You can color the image content with direct selection tool, and color the container with selection tool. So a one channel image becomes 2 colors.

                                       

                                      The colors are swatches, which themselves can contain more than one ink. If both the content swatch color and the container swatch color are CMYK, you have created a 4C DeviceN image.

                                       

                                      In Illy you can colorize a grayscale image, but not the background. It's like the swatches - you may be able to simulate Device N but you simply cannot create it.

                                       

                                      With a Device N image, the inks and channels are two different things. Of course in Photoshop they are the same thing. So you have to work around that.

                                       

                                      In Neo, when working with Device N, a user has the option of mapping an ink to a channel. You also have the option of inverting. So if I wanted to, for the Cyan ink, I could use the Magenta channel and invert it. Furthermore I can use any of my channels to create a soft mask, and invert that too. This creates a knock out when the image is on top of a background color.

                                       

                                      In InDesign you cannot work with placed CMYK images in this fashion. The Device N editing for images only works with placed grayscale images (which aren't really grayscale, not in InDesign anyway).

                                       

                                      In Photoshop there are a few "Device N-like" features:

                                       

                                      1. In the layers, with Layer Style you can designate channels under Advanced Blending

                                       

                                      2. The Channel Mixer adjustment. With this you can effectively remap channels.

                                       

                                      3. Spot color solidity. This one is interesting. When it's a spot channel it's purely a visual thing. But when the channel is merged, the solidity setting impacts the merged result.

                                       

                                      In Photoshop, here is a neat way to simulate a Device N 4C image:

                                       

                                      1. Start with a CMYK image.

                                       

                                      2. Create 4 solid fill color layers. Each fill is 100C 100M 100Y 100K

                                       

                                      3. Name each layer Cyan, Magenta, Yellow, Black

                                       

                                      4. Group all the layers and name the group "Device N"

                                       

                                      5. Hide the group

                                       

                                      6. Load the Cyan channel as a selection. Invert the selection. Select the cyan layer you made earlier. Use the selection to make a layer mask.

                                       

                                      7. Under Layer Style, check on the C channel only.

                                       

                                      8. Follow the same logic in steps 6 and 7 for the other 3 separations.

                                       

                                      9. Show the group. This is your original image, but white is now transparent. You've lifted the inks, ripped them away from the white.

                                       

                                      10. Underneath the group layer make a white layer. Normally this represents the background (paper). But you are free to color this whatever you want.

                                       

                                      11. For the group - you are free to make a separate mask for it too, if you want. This way the image can knock out of the background.

                                       

                                      12. One cool thing you can do. In each color fill layer, you could make all the channel designations the same. So make them all cyan. Now you have composted all the CMYK image data into the cyan channel, and the other channels are empty. This is like using the channel mixer, if you added 100% of all 4 channels into a single output channel. With the layer configuration, you have lost no information – the original image can still be restored, by reconfiguring the channel designations.

                                       

                                      Of course the problem comes with the spot colors, which cannot participate in layer interactions. Possible with Device N, but not with Photoshop.

                                       

                                      Also very easy to simulate a single channel Device N in Photoshop with Duotone. Start with a grayscale image, Mode: Duotone. Designate 2 inks. Ink 1 is a normal linear curve. Ink 2 – make 0:100, and 100:0.

                                       

                                      Now everywhere you have exactly 100% ink coverage. Each ink is an inversion of the other. But being duotone, you're cheating with the curves... you're simulating 2 channels but you only have one.

                                       

                                      I think the key to understanding Device N - there's always the option for a different background (container) color. Also there is the option for an extra channel, to create a knock out in the background color. So a 4 channel image may really be a 5 channel image. And the inks and the channels - well they are not the same thing, not in Device N.

                                       

                                      At this point I'm confusing myself. Either I'm on the right track or this is a bunch of BS.

                                      • 16. Re: Overprinting gradient fills
                                        Steve Fairbairn Level 5

                                        Got you, sort of.

                                        I have tried doing this sort of thing myself, saving CMYK separations of an image as greyscale tiffs and then recolouring them with spot colours with each set to multiply. If everything is aligned properly you get what looks like a single image in strange colours. Spot channels look o.k. in Acrobat output preview.

                                        I have also tried colouring each in its correct colour - doing this results in what looks like an ordinary CMYK image.

                                         

                                        The problem is getting things to rip properly. Even when the job is saved out as a pdf some rips seem to have trouble with this method. Not sure why though.

                                        • 17. Re: Overprinting gradient fills
                                          Printer_Rick Level 4

                                          steve fairbairn wrote:

                                           

                                          What is the problem with adding channels to layers (or as layers)?

                                          There is a workaround but it's not the best.

                                           

                                          Provided you have a spot channel, load as selection, make a color fill layer (matching the spot color definition) with inverted selection as a mask. Set this to multiply.

                                           

                                          In InDesign there is the option of turning off this layer's visibility when placing the PSD. So really it's a non-printing layer, just there to represent the spot plate on a layer. I don't know if AI has the capacity to turn off layer visibility in imported Photoshop files.

                                           

                                          To simulate solidity in Photoshop with the "spot" layer, duplicate the layer below, change fill to white and blend to normal. Now change the opacity of the white layer. This underlying white fill replicates spot color solidity.

                                           

                                          Of course all of this is just to show what life would be like if spot colors really could interact with layers...

                                          • 18. Re: Overprinting gradient fills
                                            Printer_Rick Level 4

                                            steve fairbairn wrote:

                                             

                                             

                                             

                                            The problem is getting things to rip properly. Even when the job is saved out as a pdf some rips seem to have trouble with this method. Not sure why though.

                                            Older RIPs may have trouble with the blend mode. You could use overprint instead. The construct would be different (simpler) in the PDF but the separations would be the same.

                                            • 19. Re: Overprinting gradient fills
                                              Steve Fairbairn Level 5

                                              Exactly. In this case overprint would get you to exactly the same place as multiply except that you'd need to use the overprint preview to see it in Illie.