i have four identical layers on top of each other and photoshop exports like there's only one layer

[paularusu]

hi there!

i'll try to be brief with my problem: i am working on a poster series for which the entire type is rasterized in one single layer, some bits of it are blurred, but the blur is made with noise -- i have attached a screenshot.

in order for it to look like in the screenshot, i've made duplicates of the layer -- in total i have four copies of it. if i leave just one layer, the type looks a bit flimsier. 

when i export to pdf though it renders just one layer of type, it's like the others don't exist. if i merge all layers the same thing happens, it ignores the duplicate layers and the flattened image looks like it only has one layer of type. i tried making a new document and dragging all my layers to it but i encounter the same problem. 

what's weirder is that i made some other graphics earlier today from the same series and it exported just fine then. 

anyone got any clues as to what this could be?

[davescm · Accepted solution]

Always view the image, before and after flattening (or merging) at 100% zoom. That is particularly important with images containing noise. When zoomed to less than 100% the preview averages the pixels on each layer to the current zoom level then blends them. However, when actually flattening, or merging, each image pixel is blended individually. When using 100% zoom, which in Photoshop means 1 image pixel is displayed per screen pixel, the blending should match.

Dave

[paularusu]

hah, yes, you're right, it matches! this is so strange, how this happened all of a sudden (i've been working with these layouts for two months)

thank you so much, it's been driving me nuts!

[davescm]

Photoshop has always blended previews like this. It is done thst way for speed. On many images it is barely noticable. But when images contain fine noise the difference can be significant. The correct view is at 100% zoom, so it is always worth checking.

Dave