Railwire Gallery Photo Color

[Dave V]

I'm wondering if I'm the only one for whom this is happening...  I use the HDR setting on my iPhone for most of my model railroad photos so they're pretty big.  I know they get compressed in terms of resolution when upload them to the Railwire gallery.  But I also notice a shift in color to duller, more muted, and cooler hues.  And yeah, I'm probably not using the right words to describe it, but see if you can see what I mean.

Just took a photo of my new track cleaner car in consist.  This is the original photo as I uploaded it to my public RGS Facebook page:



This is the photo from the Railwire gallery:



The yellows, greens, and even the oxides and browns of the railcars themselves appear brighter, warmer, and more vivid in the first image.

Now, let me be clear...I'm not complaining about the Railwire photo hosting service.  It's been an amazing resource in the light of the Picasa and Photobucket implosions.  I'm just curious if:

1) anyone else has experienced this and

2) if there's a way to restore the color and brightness of my images when I'm using the gallery.

Thanks!

[Chris333]

They both look good on my potato 

[wazzou]

They aren't as sharp either, IMO.

[Dave V]

They aren't as sharp either, IMO.

No they're not...and I'm guessing they're being compressed to optimize storage space.  I'm guessing also the compression also includes scaling down the number of distinct colors...what I don't get is why that also means muting the more vibrant ones.

[peteski]

Looking at both photos, the bottom one looks to be more compressed. Details are a bit blurred and the colors are more muted.

Just to verify, can you down-sample your original photo locally on your computer to be no more than 1280 pixels across and upload it to TRW gallery? I think that if the forum' uploader is presented with a small enough photo (<1280 pixels across), it will not change the file's contents (ie. compress the heck of it).

Once the photo is uploaded to the gallery, you can then download that photo back to your computer and compare the file size to the original photo.  The file size should be very close to the original.

[C855B]

...Just to verify, can you down-sample your original photo locally on your computer to be no more than 1280 pixels across and upload it to TRW gallery? I think that if the forum' uploader is presented with a small enough photo (<1280 pixels across), it will not change the file's contents (ie. compress the heck of it). ...

The gallery's auto-reduction was to 1024 x 768, from 2048 x 1536. Uploading your own 1024-wide version is a good idea. There may be something going on with the gallery's pixel-averaging algorithm in the size reduction. I looked at the file sizes and the TRW version is not particularly compressed versus the FB original - 142KB vs. 394KB. This is roughly proportional to the pixel count reduction, JPEG algorithm tweaks aside.

Something to consider in the gallery upload processing is the watermarking, which does change the file content. Whether that plays into or is part of some manner of re-rendering will only be determined by a test with the same 1024-wide image hosted externally versus uploaded to the gallery.

[wcfn100]

I think this all related to the GD php module that the gallery uses.

The fuzzyness is just normal compression. The color change is due to the GD module using a different color pallette than the original picture.

Jason

[Dave V]

I think this all related to the GD php module that the gallery uses.

The fuzzyness is just normal compression. The color change is due to the GD module using a different color pallette than the original picture.

Jason

This is what I was wondering about...the different color pallete.

[C855B]

Palette = color profile, a/k/a color space. I looked at the image data from both, evidently the PHP algorithm is throwing away the ICC color profile, I guess to reduce file size (by ~10%). Explains the loss of dynamic range.

[MK]

Oh!  Get rid of the ICC profile and you can be sure that there will be a shift in colors.

[Dave V]

Palette = color profile, a/k/a color space. I looked at the image data from both, evidently the PHP algorithm is throwing away the ICC color profile, I guess to reduce file size (by ~10%). Explains the loss of dynamic range.

Oh!  Get rid of the ICC profile and you can be sure that there will be a shift in colors.

Auf Englisch, bitte?

[wcfn100]

Palette = color profile, a/k/a color space.

Thx Mike, I thought about changing that to be more clear but went to bed instead.

I should also clarify that the GD module actually just strips the color profile out of the image (doesn't replace it)  which is why the more vibrant colors are gone.

One work around is supposed to be to save your image on you computer with the sRGB profile.  I tried this with Dave's shot.

First is the good one not in the gallery.  Then the one I resaved as sRGB and loaded to the gallery.  Finally Dave's gallery one.







Definitely better, but still some shift.

Jason

[chicken45]

This is what happens when you use ad blockers!

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

[C855B]

Auf Englisch, bitte?

Dynamic range: whiter whites, brighter colors (and blacker blacks).

JPEG files normally have an internal palette called an ICC profile. There are common "standard" profiles - "sRGB", for instance. Since most of these profiles define a nonlinear relationship, stripping them out will usually result in some sort of default palette which is linear. In the case of the most obvious loss of brilliance, the yellows, my take is the yellow in your original image is a high value reduced by the profile (again, non-linear), and the duller image is taking that reduced value as "the end result" using a straight 0-255 x 0-255 x 0-255 scale.

I don't know if you have any familiarity with audio modes, but it's like listening to a heavily Dolby-compressed recording without the decompression on your end. You hear the music and it seems all there, but doesn't sound quite right.

[tom mann]

This is what happens when you use ad blockers!

lol. I up the compression for the complainers.