Overprint Issue

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    • #98264
      Bala S
      Participant

      I have an InDesign document with Black color MathType equations placed over the colored background frame. When I switched off black color, MathType eps shows as white text instead of hiding.

      To avoid this overprint issue, I am using Transparency setting of MathType eps to Multiply. After applying Transparency/blending to Multiply, If we switch off black color, then we are not facing the overprint color issue. But I wonder, will output quality of Black color equations be affected while printing. Can anyone confirm is this the right choice to avoid overprint issues of MathType eps placed over the colored background box? or any other suggestions to aovoid overprint issues in InDesign?

    • #98265
      David Blatner
      Keymaster

      Should be okay, but you can test it by opening Window > Output > Separations Preview. That will help you determine what is getting knocked out and what each plate will look like.

    • #98288
      Bala S
      Participant

      Hi David Blatner,

      Thanks for your reply and I had ensured that overprint issues are resolved. But my thinking is, will Equation black display percentage be dull while printing? When I checked the PDF visually, there is no huge difference before and after applied transparency.

      Current situation is, Orange color background frame and MathType eps are placed over that box? Because of using transparency, will orange and black color be merged together and will produce the difference in the High Quality Printer? If yes, I have to search and see other options.

    • #98318

      Isn’t the original situation the behaviour of a proper separation? If the characters in the equations are black, they will knock out any background colour by default; turning off the Black will show that knockout (the absence of any colours) as white in the shape of the characters, which is technically different than white text on a colour background. If you overprint, then the background colour will be untouched and added to the Black, turning it into a rich black, and the equations will definitely be darker than any surrounding black text. I don’t think anything needs to be done to those equations.

    • #98320

      A note: the Multiply command used in transparency has the same effect than an overprint.

    • #98323
      Graham Park
      Member

      Lynda
      Proper trapping of black text on a colour background is for it to overprint.
      Text is usually too small to trap (knock out, choke and spread) and would lead to problems when printing.
      You will get a rick black which is correct, you will not be able to see this colour in bodies text as it is too small.

      If you want the seps to look more correct then set the black text in Illustrator to overprint before you save it.

      As to the original question your prepress/printer will add their own trapping to text and will usually over ride you settings to make sure they are correct for their print process. Workflow systems (Prinergy, Apogee, XMF, Esko etc) will apply trapping as part of the press press along wiht colour management.
      So the separations you see inInDesign are not always the same as what the printer will end up using.

    • #98433

      Graham,

      You’re absolutely right. I was thinking about black text for larger print, like a poster. But we’re talking about MathType equations, they’re obviously small, hence your answer is the correct one.

    • #98607
      Bala S
      Participant

      Hi Lynda and Graham Park,

      Thank you so much for your detailed explanation and I gathered lot of information form your statements. However If we apply transparency to MathType eps, definitely there are some visual differences in the high quality print output (between equation black text and normal black text).

      Hence I am requesting customer to leave as it is right now for MathType eps overprint issues.

    • #98608
      Graham Park
      Member

      The best solution is to set make sure all text is the same 100K and all black text to overprint and do the same in the EPS file.
      That is in Illustrator set all the black text to be overprint.
      This way all the text will be the same and will print the same.

    • #98622
      Bob Mathews
      Member

      Thanks for the thread. I wanted to add that we’re adding overprint/knockout options, that will be coming soon to a MathType near you. Our highest priority is releasing an Office 2016-compatible version for Mac, but after that we plan more frequent releases beginning hopefully around the first of the year. Look for it then or soon after.

      Bob Mathews
      WIRIS Science
      Makers of MathType

    • #98637
      Bala S
      Participant

      Hi Bob Mathews,

      Thanks you so much for your information. If MathType resolves overprint/knockout issue, then we will get relief from huge head ache.

      Bala. S

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