Do the values change or only the appearance on the screen. There are some known issues when transparency comes into the game that the screen preview in InDesign changes.
It only happens on greyscale images. If the image is CMYK (or RGB) they are not affected by adjusting a different obect's opacity.
If there's no transparency on the page do you also get the change when you turn on Overprint Preview?
InDesign color manages grayscales differently depending whether you have OP turned on or off. With Overprint off the preview of grayscale objects is sGray (sRGB or 2.2 gamma), which is useful if you are designing for screens. With Overprint on, the preview shows how the grayscale is expected to print on the black plate, and your document's CMYK profile affects the preview. If the assigned profile is a newsprint profile the change would be more noticeable because of newsprint's lack of dynamic range. That simulation would carry over to Acrobat if you export with a PDF/X preset
If your Transparency Blend space is CMYK adding transparency also forces the newsprint CMYK preview.
Here my assigned profile is ISO Newspaper v4 26
Only the appearance on screen (and output as PDF or printing to office printer) changes. The opacity values for the greyscale image remain at 100%.
Thank you Rob for your reply and explanation.
No it doesn't happen if Overprint Preview (view menu > overprint preview) is selected. As soon as Overprint Preview is turned on, the greyscale image immediately drops in contrast - it looks lighter/fainter on screen.
No it doesn't happen if Overprint Preview (view menu > overprint preview) is selected.
As soon as Overprint Preview is turned on, the greyscale image immediately drops in contrast - it looks lighter/fainter on screen.
You mean yes it happens (the contrast change) with Overprint Turned on?
Only the appearance on screen (and output as PDF or printing to office printer) changes.
You can check the actual output values via InDesign's Separation Preview's separation numbers, or AcrobatPro's Output Preview. You shouldn't be seeing placed grayscale output values changing in either app.
Here are two similar threads, which also describe how to set up Photoshop's Grayscale color management;
Apologies...i should've worded it better.
Answering your first question: "...do you also get the change when you turn on Overprint Preview"
No...the image doesn't change in appearance when adjusting the opacity of the other object/shape on the page, when the Overprint Preview is turned on beforehand.
Thank you for your explanation about how Overprint Preview shows how the greyscale image is expected to print on the black plate.
I'll just turn on Overprint Preview when i'm working on an ad for newsprint when using a greyscale image.