Loss of Sharpness After Copying

[Tom Zimberoff]

In Affinity Photo v2.3.1, if I copy a TIF file (with multiple layers) or Export it as a JPG . . . OR flatten the multi-layered TIF, sharpness is lost in the background (i.e., the sky and clouds). As far as I can tell, I did not create a separate sharpened layer (or use Clarity) for the background. The only sharpened layer applies to the background layer as a whole and was applied before making further edits.

If you A:B compare the attached screenshots, you can see what changes. Does anybody know what's going on here?

[GarryP]

I can’t give an answer to this, it’s not an area I have much knowledge of, but I can give two tips which might help you to get an answer more quickly.

When posting images for comparison…

Tip 1: The forum software can often ‘mess around with’ images that are posted – changing colour space etc. – so that the images we see in the forums can be different to those that you uploaded. Because of this, when you would like people to compare two or more images, it is often useful to ZIP the images and then upload the ZIP. This keeps the images as you see them which makes it easier for us to see what you are seeing, rather than what the forum software is showing us.

Tip 2: When the differences between the images are subtle, and/or the images are large, it’s better if you give us the locations of some specific areas which you want us to look at. You might have been looking at the images for hours but we are seeing them for the first time and don’t know which parts of the images you have been concentrating on. The more specific details about the problem that we have the better we can help you.

[stokerg]

Hi @Tom Zimberoff,

If you view the image at 100% zoom, how does the background look then?

Would you be able to upload your afphoto file, the one with the adjustments to our Dropbox here?

[Tom Zimberoff]

I don't usually create an afphoto file; I go straight from either 3FR or fff (Hasselblad) to TIF, then make high-res JPGs.

The issue I'm referring to is subtle but noticeable. I will upload the files. 

If you compare the files, even without zooming in, look at the sky/clouds in the center of the images and see how it becomes "softer" when you switch back and forth from TIF to JPG.

©2024 Tom Zimberoff_#3B_0185.tif

[Pšenda]

16 minutes ago, Tom Zimberoff said:

If you compare the files, even without zooming in

Image comparisons, especially regarding sharpness, should be done at 100% (image pixel to monitor pixel). Otherwise, using the mipmaps method causes distortion at smaller magnifications.

[Tom Zimberoff]

That seems ridiculous to me. It's either sharp or it's not. If you can see the difference with your naked eyes on a computer screen, what the heck do you think a five-foot-wide print will look like?

[Pšenda]

54 minutes ago, Tom Zimberoff said:

what the heck do you think a five-foot-wide print will look like?

Any relation to the recommendation - compare images/their sharpness on screen at 100% magnification?, as already recommended the moderator.

P.S. Of course, JPEG is lossy by its very nature (and it doesn't matter if it's hi-res, it only depends on its quality/compression rate), so there is a loss of detail and thus a loss of sharpness.

[R C-R]

1 hour ago, Tom Zimberoff said:

That seems ridiculous to me. It's either sharp or it's not.

"It" can refer to two different things, the sharpness of the screen rendering of the image or the sharpness in the actual image file. They are not the same thing, which, due to the mipmap rendering method, is why you need to view the file at 100% magnification to make a valid evaluation of the file's actual sharpness.

[Tom Zimberoff]

The thing is, my kind interlocutors, I'm not talking about resolution. And I'm not talking about lossless conversions or any such thing. I'm talking about one part of an image — NOT the whole thing, that is less sharp when converting from a 300dpi TIF to a 300dpi JPG at the same dimensions. For years, I have routinely made very high-resolution JPGs for printing. There is no difference, as expected. For years, I have never seen a difference between the TIF and the JPG on a screen, either, regardless of magnification. There should be NO difference. And it's apparent in only a part of the image. That is what has prompted my concern.

[R C-R]

3 minutes ago, Tom Zimberoff said:

I'm talking about one part of an image — NOT the whole thing, that is less sharp when converting from a 300dpi TIF to a 300dpi JPG at the same dimensions.

JPEG is inherently a lossy file format so regardless of the export quality setting there will be some loss of sharpness compared to a lossless file format like TIFF.

[NotMyFault]

Your tiff is RGB/8 and AdobeRGB. The jpeg is RGB/8 and sRGB.

i tried to convert (in one step) the tiff to RGB/8 and got severe color changes (on iPad).

I assume the issue is due to color format changes. The filters and adjustments can change their effect based on color format. Some internally convert to hsv/hsl, others directly modify the color values. E.g. threshold can give totally different results, as a change in color format tries to give same rendering, but color values may change from e.g. 49 to 50 so threshold flips from black to white.

JPEG with max 8 bit color channel depth can have banding effects.

this all does not full explain the difference. 
plead provide screenshots or a screen recording showing these essential steps:

• tif file before export to jpeg
• export to jpg (all export settings, color format, color profile, quality settings, matting color, resolution, …)
• zip both files and upload zip to ensure forum software has no impact to uploaded files.
• save tiff with history as afphoto file so we can reproduce your steps exactly.

[NotMyFault]

Found the cause: It is the noise removal filter nested to background.

it needs several seconds to render, and only renders at 100%.

So your crispy looking tiff simply misses the noise removal, which is included in every export.

@Tom Zimberoff