Appearance of white over transparent (offwhite) changed in latest versions

[topouzid]

I'm creating some white logos on transparent background, and in order to make it visible and edit them easier, I've set my Document Setup transparency a bit offwhite (grey or beige) and enabled the "Simulate colored paper". Having it setup this way, up until 2 weeks ago, the background of the artboards looked offwhite, and the logos appeared white making easy to edit them or see whatever logo is on each artboard. On export I was getting the white logo on transparent background. It was the perfect work environment. 

After the past updates (v28.2) the artboard looks offwhite as I'm setting in on Document Setup, but my whites appear transparent. If I set the paper to blue and my ink to yellow, the logo appears green. That's great if I want to simulate inkjet or pantone ink, but some graphite (laser toner) isn't transparent, so picking yellow ink over blue paper should appear yellow, and picking white color over a black paper should appear white. Is there a way to simulate 100% covering color instead of inkjet color and make whites appear whiter than an offwhite background? It used to be like that about 10 or 20 days ago.

[Ton Frederiks]

It is better to create a layer (set to not print) in the back with an off white filled rectangle to simulate what you want.

[topouzid]

A layer set not to print still exports to png (which I usually do in my workflow). I've read that 

• To create artwork that does not print or export, even when visible on the artboard, select Template in the Layer Options dialog box.

Yet, if I create a grey box at a bottom layer, I can clearly see my white logos, but even though the bottom layer is set as a Template Layer (it has my gray boxes and isn't supposed to be printed or exported), yet if I "Export for Screens", my png file has grey background, so the template gets exported.

I toggle the visibility (on while editing, off while exporting or printing), but that's an extra step and not the correct way to do it.

[Doug A Roberts]

Can you show your Illustrator window with an object selected and appearance/attributes panels visible?

[topouzid]

You can see in the screenshot that the artboards look offwhite and the logos where color is white (rgb255.255.255) aren't visible. The same logos appear white on offwhite background on the "Export for Screens" preview. Just about 2 weeks ago, my artboards looked exactly like the "Export for Screens". Then I got an update and with this update the whites appear as a simulated inkjet/pantone ink instead of a simulated opaque paint.

[Doug A Roberts]

Is it possibly because you are using CPU preview? Testing just now, CPU preview shows overprints, while GPU preview does not.

[topouzid]

This might be it. My GPU Performance is disabled and greyed out (Intel Iris Xe). The latest update might have broken support and it shows as incompatible. I don't specifically remember it being turned on, but I think it actually was. It's the embedded graphics processor of an Intel i7-13700H. It might also be possible that Intel GPU had an update during that period.

[Ton Frederiks]

The problem with your approach is that white is the paper color and if you change the paper color you change the appearance of white.

[topouzid]

What's the correct approach to simulate white opaque ink on a grey paper? The appearance of white should be different than paper color. In a matter of fact, there should be a way to simulate opaque colors and ink colors, so an ink yellow should blend to the color paper, while an opaque color shouldn't.