TESTING image sizes again. TIF upload for you to play with in Post #12.

[Andrea B.]

TEST:  Post 1800 px max width. Does it also look good within the post at 1100 px?

 

TEST:  Post big image. How is it affected by the forum software resizing to 1100 px/1800 px? Does it still look ok?

 

Images to arrive soon.......

[Andrea B.]

This Teddy Bear Sunflower image is 7360 x 4912 px. It is a monster by website posting standards. It was converted in Luminar. Some detail and sharpening was brushed onto the flower only. To see anything at full size, you will need to click it up 3 times. 

 

Some of you will experience a slow load of this big image. That's why we ask that you do resize images before posting.

 

I want to see how the forum software resizes this full-size image for display with a post and within a black box. Next I'll post a resize of the Teddy Bear to 1100 px and 1800 px and make comparisons.

 

Labels and conversions to JPG were made in Photo Mechanic.

 

Important factor affecting this test:  I am resizing in Photo Mechanic. Different apps may resize with better or worse results. 

 

 

D810 + Micro-Nikkor 60/2.8G

f/11 for 1/60" @ ISO-400

Processed in Luminar.

Full-size.

 

Resized the NEF in Photo Mechanic and saved to a TIFF. Then processed in Luminar.

1800 px max width.

 

Resized the NEF in Photo Mechanic and saved to a TIFF. Then processed in Luminar.

1100 px max width.

[photoni]

A while ago I did some tests.
If I posted a Jpg saved with Photoshop with quality 3 - 5 - 8 - 10 - 12 the brouser rewrote them with a weight/quality similar to Photoshop 8
So since that time, I have been shipping to UVP Jpg with quality 8.
.
I don't understand why your first image weighs so much ... 26.7 MB
what does 39.65MB at Q100 mean?
.
I downloaded your photo and entered my Exif data (yours are missing) and saved with photoshop quality 8
my file weight is 4.541 MB
check now.

Now it weighs 14.4 MB ... I think that is now a problem !

 

P.S.

I know them under the name "Vincent Van Gogh's Sunflowers" with photos with the "wet plate" are black

[Andrea B.]

Well big flappingdoodle dangrabbity.

I should have made that sizing test WITHOUT sharpening or adding detailing to the images.

 

I also note that the monstrously large image looks, so far, to be the best one at 1100 px and 1800 px. Not what I was hoping to achieve.

 

Do note that I have never claimed to be any good at either resizing or sharpening. La !! 

I'm going to blame it on the heat. 

 

These next three images are the original and two resizes with NO processing. Not that I did much above except for cloning out a dust bunny and the attempts to sharpen.]

 

Monster image. No processing.

1800 px, resize only.

1100 px, resize only.

[Andrea B.]

Toni, for the purposes of this testing, I saved at the highest possible quality because I am want to see how the forum software behaves. That is why my uploads weigh so much. Q100 = highest quality on a scale of 0 to 100 when resizing in Photo Mechanic.

 

**********

 

For the unprocessed images, again the huge image looks best within the post. But we cannot be uploading such big images else the forum will be very slow loading. 

 

Thus I need to figure out how best to edit the resized images so that they appear as nicely as the big one.

[photoni]

3 minutes ago, Andrea B. said:

Toni, for the purposes of this testing, I saved at the highest possible quality because I am want to see how the forum software behaves. That is why my uploads weight so much.

I repeat, the files are rewritten, regardless of the quality in which you save them.

[Andrea B.]

Toni, this forum software does not change the uploaded image. I just compared an original image with a posted one in PS. (I dragged the posted image off the page.) I layered the two images and set layers to Difference. There was no difference. Nothing actually changes in the file.

 

The images are displayed "dynamically". The display size can change. But the uploaded file does not change.

 

I was WRONG!! 

[Andrea B.]

Here is the 7360 x 4912 image saved at Q100, the highest quality.

Here is that image saved at Q70.

[Andrea B.]

Here is a screenshot I made of the two preceding images displayed at full size. One-half is from the Q100 image and the other half is from the Q70 image. Can you tell the difference? (No sharpening was done on either image. Obvious when viewed this way.)

Be sure to make 3 click-ups to get the largest view on an expanded browser.

[Andrea B.]

To understand how dynamic resizing works, bring up an image in PS. Next select the Image Transform tool labeled Free Transform. That puts a frame around your image with corner squares. Grab a corner square and move it back and forth along the image diagonal. You are dynamically resizing the image.

[Andrea B.]

So the question becomes: what can I do to make the 1100 px wide  image look as good as the resized 7360 px wide image?

 

[Andrea B.]

If you would like to help find the answer to my preceding question, here is the image to play with. I'm uploading a humongous sized tif, so that it can be properly edited. Figure out how to make it look good when a hard resize is applied for 1100 px width or 1800 px width.

teddyBearSunflowerBIGNoEdits.tif

[Andrea B.]

1100 px with Detail 15 (only) from Photo Ninja.

 

[Andrea B.]

1100 px with Detail 25 (only) from Photo Ninja. That is rather an astronomical value for PN's Detail slider.

[Andrea B.]

1100 px with Luminar Small Detail50.

[Andrea B.]

1100 px with Luminar Sharpen 100.

This doesn't seem to do anything?

[Andrea B.]

I've worn out my eyes. Everything looks the same. Time for a break.

[photoni]

Andrea, I'm not a programmer, I'm a still life photographer who has been using Photoshop since 1994. I have my preconceptions, but a simple test demonstrates the differences in compression and file size... here
.

Each image stored on the UVP server is not the original, does not have the same compression, does not have the same name.

it's rewritten! it is useless to upload it at maximum quality because it is rewritten with a different compression from the original

(I think similar to photoshop 8/12)

.

I used Tiff for my tests

In my image, the gradient above is 0 to 75/255 B>W

below is 0 to 255/255 sRGB levels

 

.

The new name is - B12.jpg.7074dfd3b9dba1cee51822c559daaf90 - 3.058 MB - smaller file ?!?!?!

 

.

The new name is  - B3.jpg.cccda923f900a65e238ce1a9bf708ad7 - 1.326 MB - much larger file

 

 

.

 

 

[photoni]

I redid the test with @Andrea B. 8bit Tiff file

[Andrea B.]

I do not understand the sequence of events.

 

You downloaded the sunflower TIFF file?

You resized it to 3601 x 2291?

You saved it as a JPG with quality 12/12?

 

What did you do next?

 

[photoni]

Yes, I have downloaded your Tiff
I cropped it (3601X2291 pixels) so as not to weigh too much on the image  
I put two gradients
up, from 0 to 75 levels out of 255
down, from 0 to 255 levels
I kept the sRGB color profile
.
the first file is saved in Jpeg format with quality 12 out of 12 ... it weighs 3.200 MB
the rewritten file on the server weighs ... 3.058 MB
.
the second file is saved in Jpeg format with quality 3 out of 12 ... it weighs 0.303 MB
the rewritten file on the server weighs ... 1.326 MB

.

as you can see the soft rewrites the images on the server
I don't know if it can be disabled.

.

Andrea how are you ? ... that's more important !

[Andy Perrin]

I tried cropping a 2000x2000px bit of the original TIFF, saving in PS at JPG level 3/12, and then dropping it into this post. On my hard drive the JPG is 197KB.

 

If I then click through and save the image back to my computer, the saved version is 1.2MB! It seems to be as Photoni says.

 

 

 

[Andrea B.]

Toni, thank you for the additional info. Andy, thanks for your observation.

 

We were slightly crossing wires, so let me try to clarify.

 

When you upload a JPG to our forum, it gets either a GD "wrapper" or an ImageMagick "wrapper" so that thumbnails of various sizes can be displayed by the forum software. If you compare your original file to the file that has been dragged off the browser, then yes, you will see different filesizes due to the added "wrapper". (I don't know the exact terminology there, so I'm using the word "wrapper".)

 

Added 31 July 2023 by Admin:  It is true that EXIF is stripped and that the uploaded FILE is "wrapped" by GD. So filesize changes are observed. It is possible that the filesize change is either a decrease or an increase.

What I am trying to determine is whether or not the file quality is changed? If I compare an original file to the dragged-off, wrapped file, I cannot see any differences in the pixels.

 

Added 31 July 2023 by Admin:  Yes, JPG files are changed by the forum software. No, PNG files are not changed by the forum software.

 

I do not know if any EXIF is written to uploaded files by either CD or ImageMagick. I'll go find my EXIF reader and check that and report back.

[Andrea B.]

I have some new information about what's happening to posted files.

I'm looking at one of the original files uploaded above and its website version (dragged off the page).

 

Original File: teddyBearSunflowerBIGNoEdits.jpg

Metadata takes 8.29 KB (0.1%) of this image.

File Size: 11.6 MB

Image Size:  7360 x 4912 px

Creator:  Andrea G Blum

 

Website File:  teddyBearSunflower.jpg.b753c6805e064f853987b801a32f99f3.jpg

Metadata takes 80 bytes of this image.

File Size:  10.4 MB

Image Size:  7360 x 4912 px

Creator: gd-jpeg v1.0 (using IJG JPEG v62), quality = 100

 

Currently for image support, GD is turned on in our forum software settings.

Upon upload of a JPG, most of the original EXIF is stripped out by GD.

The uploaded filesize is therefore smaller than the original filesize.

 

GD quality is set to 100 so that no change is made to the image pixels.

The image dimensions are not changed permanently

because I have not set any restrictions on dimensions.

The image is dynamically resized depending on where it is viewed:

in a post, in the black box or on a browser page.

 

It is possible that the uploaded filesize becomes slightly larger

when the original file has no EXIF because GD adds its own Creator string if there isn't one.

(I don't have time to pin down exactly what GD adds if EXIF is missing entirely.)

 

 

[Andy Perrin]

Andrea, taking the difference of the website file and the original in PS and then doing an auto contrast shows the quality has changed.

 

 

 

Also, the file size increase from 197KB to 1.2MB is not explainable by anything with EXIF data (which is tiny!). That's a HUGE increase in file size.