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Question

Multiply function in effects

Forum|Forum|8 years ago
April 1, 2018
7 replies
1844 views

Hi. In InDesign, when I set an image to Multiply (in effects), all images screen back.

Why do images screen back when using the multiply function?

This topic has been closed for replies.

stephenp62942288Author

Participating Frequently

Hi. How do you adjust your Transparency Blend Space?

Barb Binder

Community Expert

Edit > Transparency Blend Space

~Barb at Rocky Mountain Training

stephenp62942288Author

Participating Frequently

It also happens when the "A" and "B" drawings are grayscale JPEG files.

rob day

Community Expert

It's expected behavior with grayscale images.

Set your Transparency Blend Space to RGB and the preview won't change, but if you are outputting separations for a printing press the RGB blend space will convert the grayscale to 4-color CMYK. You can use the Separation Preview panel to check the expected output values.

Here are a couple of related threads on grayscale color management:

Re: Grayscale images showing up too dark

Re: Grayscale images with alpha channel get lighter?

stephenp62942288Author

Participating Frequently

Barb Binder

Community Expert

Hi Stephen:

Let's back up a second and talk about blending modes: they blend the pixels on top with the pixels underneath to produce a new effect. Multiply will darken the dark pixels and leave the light ones alone. It's a common technique used in Photoshop to enhance the contrast and pull out details in old faded b/w photos (but my screen shots are in InDesign since that is where you are working).

Original photo:

Duplicate copy on top, blending mode set to Multiply:

Multiply always darkens, which you seem to understand, so I'm curious Stephen, what is under your b/w images—what are you blending with?

~Barb

~Barb at Rocky Mountain Training

rob day

Community Expert

Barb, your image's container frame must have a color fill that the image is multiplying with?

If I set the fill to [None] there's nothing to multiply and the images preview the same:

Here Multiply changes the image, but only because I have a 21% K fill behind the image

Barb Binder

Community Expert

Yes, Multiply has to interact with something. That's what I was trying to figure out—what is Stephen multiplying with first, and second how is Multiply screening back the images. I suspect your first responses are going to be the correct answer, but I was trying to go to back to figure out the workflow, which doesn't make sense to me, yet.

~Barb

~Barb at Rocky Mountain Training

rob day

Community Expert

Both images are grayscale images.

When there's a transparent object on the page and your Transparency Blend Space is set to CMYK, or you turn on Overprint Preview; grayscale images display using your document's CMYK profile. The preview might change depending on the assigned profile.

With Overprint or Separation Preview turned off grayscales preview as 2.2 Gamma or sGray. The dual preview helps if you are designing for screens and you don't want the press CMYK preview.

You can also set your Transparency Blend Space to RGB and your Multiply example won't change, but it will convert to 4-color CMYK if you export for print.

stephenp62942288Author

Participating Frequently

Do you mean that this is not just an on-screen effect? InDesign is actually altering these image, making them a lighter (screened-back) version of themselves?

And, thanks so much for the help!

Hratch Derhagopian

Inspiring

on screen effect is related to the color profile of the application it self. some use different ones, so in some applications you will see them different from each other.

The image you are using is a single color tiff, so the color you pick for it in InDesign is the one you will see.

So if you pick black (100k) you will see it in black, or if you pick some Pantone color you will see it in that color.

It will help me if you can select the image with the direct section tool and take a screenshot showing the color palate too.

Hratch Derhagopian

Inspiring

Do you have a screenshot you can share to understand what's happening exactly. I'm not sure what you mean by screen back.

stephenp62942288Author

Participating Frequently

Hi. here are two screen grabs. The first, the dog image is NOT set to multiply. Both images are accurate.

The second image has the dog image set to multiply. Both images now appear lighter than they actually are.

Conny

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