Images not as sharp?

WilliamM
12 Jun, 2018 23:51
Maybe its me, but recent uploads don't seem as sharp. Has something changed? Compared to my original and postings on Flickr and even Facebook, the "front page" image seems a little soft, almost like it was downsized a bit too much for the size shown.

Any changes or is it my imagination?

If it makes any difference I downsize from 16 bit Tif to Jpeg via Photoshop CC, "save for web legacy", max and full  size.
WilliamM
13 Jun, 2018 05:00
Still curious, but I found a variable that may be my doing. New machine  and platform (Mac to PC) and it may be handling the downsizing differently.

-William
carastro
13 Jun, 2018 09:30
I would never change an astro-image into Jpeg, this compresses the file and can cause all sorts of horrid damage.  I always upload as a PNG file.

Carole
siovene
13 Jun, 2018 11:30
JPG does not equal compression. You can have a lossless JPG just like you can have a lossy PNG.

EDIT: I am wrong. Even JPG 100 has a 2.6:1 lossy compression.
Edited 13 Jun, 2018 11:32
carlocolombo
13 Jun, 2018 11:42
carissimo Salvatore,   ti ringrazio per questo appunto,  dando questa risposta ai chiarito alcuni miei dubbi, ti saluto   c.colombo
Die_Launische_Diva
13 Jun, 2018 13:35
William Maxwell
Still curious, but I found a variable that may be my doing. New machine  and platform (Mac to PC) and it may be handling the downsizing differently.-William

Maybe it is a high-DPI scaling thing, Windows still has some problems with high-DPI monitors. I am not sure how Macs treat high-DPI monitors.

Clear Skies and Clear Monitors smile
Edited 13 Jun, 2018 13:37
zishor
13 Jun, 2018 13:50
Would be very interesting for me as well. Most of the time I am happy with my sharpness on my monitor when looking at it in Photoshop. When I export it it is ok as well on my machine but when I upload it here the previews seem softer. How do you guys export the images? Quick export to PNG? Do you downsize them?
Best Frank
WilliamM
13 Jun, 2018 14:29
Carastro
I would never change an astro-image into Jpeg, this compresses the file and can cause all sorts of horrid damage.  I always upload as a PNG file.Carole

PNG it is from now on. Thanks.
WilliamM
13 Jun, 2018 14:36
Die Launische Diva
William Maxwell
Still curious, but I found a variable that may be my doing. New machine  and platform (Mac to PC) and it may be handling the downsizing differently.-William
Maybe it is a high-DPI scaling thing, Windows still has some problems with high-DPI monitors. I am not sure how Macs treat high-DPI monitors.

Clear Skies and Clear Monitors smile

You may be onto something since the displays were all I kept being hi rez  (apple) graphics monitors. . That said, I was noticing a difference between the image uploaded here and the same uploaded to Flickr. How are all images scaled here? You have thumbnails of various sizes, what percentage is the screen first in from the smallest thumbnail (the screen with all the image info, plate solving, etc)? Is it kept in the original format, just sized differently?
siovene
13 Jun, 2018 14:40
Images are converted to JPG with 100% quality. Very small thumbnails are 80% quality.
WilliamM
13 Jun, 2018 18:41
Salvatore Iovene
Images are converted to JPG with 100% quality. Very small thumbnails are 80% quality.
Interesting. So every image we are looking at here is a jpeg?

So that would mean tif->jpeg on my end goes through another jpeg generation… humm.

I'm more familiar with the audio world, so in that lingo 24 bit wave= 16 bit tif, flac= ? (png?- lossless compression), jpeg= Mp3 (lossy compression).

Is there a way to use a lossless compression format at Astrobin as its main format?
Edited 13 Jun, 2018 18:42
WilliamM
13 Jun, 2018 20:21
edit:

Now that I have reviewed all my older images I may be totally off on my premise (below).  I would say the middle two "downsizings" are a bit too low rez. They load well,  but it seems a bit too much of a compromise on the image quality.

:::
I think I see a variable that may be causing this.

If I am correct, an image comes in and is converted into 4 sizes of jpeg:
thumbnail, size with data, larger size, and "full rez"

On my end anyway the "size with data" is showing larger . It used to always fit on the screen with all the data info, but especially the verticals no longer do so, so the same image downsizing is being viewed larger and therefor at an apparent lower resolution. The "larger size" has never looked good on my end.  I'm on Apple Cinema displays, though.  Maybe iPhones are more tolerant.

So did this variable somehow change or is it something I am doing?  I'm pretty sure the dimensions of my images haven't changed that much. Looking back over previous uploads I would say the vertical size especially has doubled in the way it is displayed on the screen.
Edited 15 Jun, 2018 15:00
 
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