Artefacts

[sthan]

Now I have artefacts on every two pics I download in the Photo section.
sRGB, 240 ppi, JPG, etc. as usual.
Originals (same specs) don't have these artefacts on my HD.
What's up ?

[sthan]

Now I have artefacts on every two pics I download in the Photo section.
sRGB, 240 ppi, JPG, etc. as usual.
Originals (same specs) don't have these artefacts on my HD.
What's up ?

[Perspectics]

I know it will be hard to present an example, since the artifacts seem be related to uploading them to the forum... but you could maybe open the browser with your pic with artefacts, and place the "clean" image in C1 (or whatever) next to it, then press "print screen" and compose a comparing image? I don't see any difference when I upload my jpgs. I use 72dpi btw because anything above 96dpi is too much for any monitor. I believe, it was like 72dpi on MAC monitors, and 96 for typical PC monitors, correct?

[sthan]

In fact, I'm perplexed, because the same series of images, with the same specs (see my last posts), some present artefacts (Lotus, for ex.) and others not a single one.

[Perspectics]

Again, is it possible to present an example, by any chance? What kind of artefacts? Color problems? Jagged JPG artefacts? Why would a jpeg with sRGB look different when uploading to a forum? Have you tried to look at your pictures using a browser URL such as file:///C:/Documents%20and%20Settings/lalalalalala/.../picname.jpg? How does it look then? Which browser? What other viewer? ...

[sthan]

Jagged JPG.
Look around the head and hand of the driver (Lotus) or the head of the walker in front of the hangar (plus the outline of the hangar itself). In the latter, neat and crisp outlines are essential. The downloaded pic is dirty. I consider cancelling it. Never had this kind of problem here before.

[jaapv]

link?

[sthan]

Thanks, Jaapv.
http://www.l-camera-forum.com/leica-...836-lotus.html
http://www.l-camera-forum.com/leica-...ave-wings.html

Same last pic on the LFI-Online, no artefacts at all :
LFI Gallery - Galerie > User galleries > Sthan

[Perspectics]

Okay, I doubled the size of the head, and yes, I can spot the typical JPG "rings" around high contrast areas, like the head and the tree. Is this what you mean? I saved the pic with 100% quality in order to not introduce new artifacts. IMHO what I see when I look at "Lotus" is a very compelling photograph with typical and absolutely acceptable artefacts (on a forum). You don't see those at home? How are you looking at it at home? In Photoshop?

[sthan]

Here, in my studio, on Apple screen, in Photoshop and Lightroom, the pic is absolutely clean and free of these light worms.
To me, they're not acceptable.
Plus, I never had these when posting on the forum.
Plus, these same pics have been posted on another website, without any artefact.
Plus, several other pics of the series (especially in low light, see here : http://www.l-camera-forum.com/leica-...ushi-fix.html).

[Perspectics]

Originally Posted by sthan

Here, in my studio, on Apple screen, in Photoshop and Lightroom, the pic is absolutely clean and free of these light worms.
To me, they're not acceptable.
Plus, I never had these when posting on the forum.
Plus, these same pics have been posted on another website, without any artefact.
Plus, several other pics of the series (especially in low light, see here : http://www.l-camera-forum.com/leica-...ushi-fix.html).

Okay, now please bare with me when I suspect something really horrible........ I mean, really, don't be mad at me, but..... Lightroom e.g. is used (at least in my home) to view DNG files. And of course they don't have compression artefacts, because of no compression.

Sorry, but I have to hunt for the simple solutions first... so, if you're looking at the very same JPG in Lightroom that you uploaded to this forum, (WHICH I ASSUME!!) then first of all forget the first abstract here, and then lets think about the format. Is the size the same in Lightroom and in the browser? I mean, pixelwise....? Because if no, maybe your pic has been reformatted by the forumsoftware to make it smaller for example?

When you save the JPG, doesn't increasing the quality help?

[sthan]

Why mad at you ?
All pics are Exported from Lightroom, checked in PS 2, equally downsized to 950 x 650 around,
and downloaded.
The whole series. In the series, two of them have artefacts, not the others.

Look at the same pic, same process, downloaded on LFI :
LFI Gallery - Galerie > User galleries > Sthan
No artefact at all.

[Perspectics]

Originally Posted by sthan

Why mad at you ?
All pics are Exported from Lightroom, checked in PS 2, equally downsized to 950 x 650 around,
and downloaded.
The whole series. In the series, two of them have artefacts, not the others.

Look at the same pic, same process, downloaded on LFI :
LFI Gallery - Galerie > User galleries > Sthan
No artefact at all.

Mad at me, because I was assuming that you compare DNG with JPG... smirk!
So, to me the miracle is solved now. Look at the attached picture - on the left side you see the Leica Gallery Picture in 100%, on the right you see the forums-pic in 100%.

The size is different, correct? This means clearly, that the forumssoftware decided that your pic is too big and downsized it in an attempt to do you a favor.

[sthan]

A plain mistake from my part. Just downloaded the oversized pic instead of this one.

[Perspectics]

Originally Posted by sthan

A plain mistake from my part. Just downloaded the oversized pic instead of this one.

Wiz wiz wiz in the water in the water sniff sniff sniff - clean! Congrats

[sthan]

Wait a minute : look at this one (204 Kb, way under the forum's limit).
The mess around the tatoo.
http://www.l-camera-forum.com/leica-...tml#post561312

[WPalank]

Johan,
I'm not sure what software you use, but in Photoshop all the Color Management gurus say that Edit> "Convert to profile">sRGB is a far better choice than >"Assign Profile">sRGB. I know, this stuff gives me a headache as well!
Hope this helps!
Cheers,

[jaapv]

If you feel lazy, Jack Fletcher sells a web-conversion action for CS3 on Getdpi.
Personally this is one of the reasons I dislike sites that take low-quality jpegs only. For some images, 400 kB or less is just not enough. I tend to convert for web using 900 wide, sharpen USM 0.4,25%,1, convert to 8 bits, convert to srgb and save jpeg in the appropriate quality for the required size. If that gives me the kind of halos you have here as well, I'll save to another site in full quality and link (sorry, dial-up users)

[WPalank]

Johan,
Another thing to consider after I read Jaap's helpful post is: When do you make the conversion from 16-bit to 8-bit? As he alludes, it should be pretty close to the last step.

To show an example, I opened the same image in Photoshop two different times. Once as an 8-bit and then as a 16 bit image (the actual image isn't important for this example, only the results).
Then I did the same PS manipulations to each image (curves, levels and Hue/saturation) and made a screenshot of each Histogram and have included it below.
You can see the extreme combing (as in hair comb) in the 8 bit image. All the white area between the black lines represents data that has been thrown away. Again, only after three manipulations.
(Johan, sorry for the simplistic explanation as I know you are an experienced shooter, but we have to remember the Forums are for everyone who have similar questions.)

[sthan]

Thanks a lot, William,

You learned me something.
In fact, I don't sharpen my pictures, only high-pass it,
which is far less destructive.
Regarding 16-bit / 8-bit, I will be more cautious.
Regarding your previous post, I'll check the difference
between the two conversions.
What puzzles me is that 2 pics are noisy in the whole
series, and not the others. They all have been shot in
abundant available light, no underexposition (hi, robx2004).
Why some are artefacted, and not others ? Especially
when I posted the same pics in another website, where
they're perfectly clean (hi again, robx2004 ).

PS : I'm impatient to see your portfolio in next LFI. Congrats.