Inconsistent image display.

[Tsuwado]

Hello,

While not exactly an Irfanview problem, I can see it and trigger it in Irfanview and I hope with your help I can understand what is happening. I edit images from my camera in Lightroom 6.14. I export them as Jpeg, 80%, sRGB color profile. Most times the images show just fine, sometimes programs show them as having a lot more noise than they should. Usually these are high ISO and darker images.

This is where IrfanView comes in. It shows the images correctly every time - except when I resize the window! I do mean the window and not the image. If I drag the side of the window and move it, it shows the bad version, as soon as I let it go, it goes back to what I'd expect.

I was hoping I could find out what is happening during that time or if this is a known phenomenon, what I could do about it.

The reason I'm looking into this: Some programs/services only show the more noisy version. Working in the tech industry I can already guess that asking for help with how my images show in their program and showing them these example images, they'll say "well IrfanView isn't my program, ask them," though my issue is not IrfanView at all, just my way of showing how one file is being displayed two different ways, and their program is displaying the worst way. Which is important to show as if they only use tools that show the bad version, they'll think they have no issue, it's just me.



This is the image as it shows normally.



This is while resizing the window and the "bad versio
n"

[j7n]

The noise was always there. It is averaged out by the resampling algorithm when you don't view the image at full size but have chosen Fit to window or window width. Resampling is usually only applied when you finish dragging and have arrived at the final window size. Without resampling, you get pixels from the source image at some interval, which results in the noise spectrum being aliased down to low frequencies instead of suppressed.

You can activate the option View -> Display Options -> Use Resample for Zooming. Then IrfanView will resample on every step of the resizing process. This can be very slow. The options from the resampling dialog are taken into account here which is not obvious. So, if you have unticked "Use fast resample filter for shrinking," the resizing will be terribly slow. Makes one appreciate how even a basic video adapter can do the fast version at 60 frames per second.

[Tsuwado]

Thank you J7n. You answered my question but you also answered it in a that didn't talk down to me or make me feel like I'm dumb.

I thought it had to do with resampling! I actually do have resampling on for fit and resizing on everywhere. My machines are beefy enough that they can handle it. In this case I actually want it off, not on when I'm reviewing pictures, when I'm enjoying them probably want it on.

SO! Armed with this I went back, fist I put the picture at 100% yeah, I see it now. Then I turned off the resampling. Seems that is what goes away when you resize the windows (not the image) you let go of the screen and it resamples. Cool, now I see it at all sizes. Also this makes since on why some services I see this, some I don't and a few, depending if I manipulate the image if it shows.

Then I figure to look at this image vs another but make sure I turn off full size embeded preview. Yeah it looks worse, lots of RGB noise. Then it hits me, I still have resampling on. Turn that off and holy fudge this image is super noisy! Trying to figure out where i went wrong, I dug into the EXIF more. So the ISO setting on this image is actually lower than the better looking ones. HOWEVER, the shutter is 1/60 on this vs 1/10 on the others. So maybe I'm running into amp noise and or photonic noise. (it was super dark but I didn't want to flash everyone and kids move pretty fast - a lot.)

Lightroom seems to resample, but I feel it also "smooths" your image too. I feel like it always does, which isn't helpful. I did a 1:1 preview in software and I can see more noise but I think the export is slightly more noisy. Looking at the RAW unresampled output I can see why!

The next things I'm going to try, since this is just for memory and going online to be shown by potato services and viewed on potatoes, I'm going to see if I can resize it a good amount with resamplying and see if that permanently makes it look better. Then from there I can see about removing the remaining noise, I have software that can try to losslely resize, so maybe even see if that takes care of it. IF that doesn't, don't know why it wouldn't, I could go really shamefully low and screenshot the resampled display.

So from left to right, RAW no resampling, Raw Resampled, Embeded Preview no resampling, Embeded resampled. Honestly it still looks a bit better here than it should.


I've ran into the raw data being different from the preview before, and the confusion that can cause but I never thought about resampling. I know it can make things look better, just like some like to record in a larger resolution and downsample the video for clearer results.

Thank you, now I know what is happening, why it's happening and have some good ideas what I can do about it, (besides more careful settings when shooting)

[j7n]

Do you have this second option active too?

https://i.imgur.com/m49V3MT.jpg

If there is a lot of high frequency noise, then lanczos resampling (with "fast" unchecked will be noticeably better). With a lot variation between light and dark, the gamma problem would also start to manifest, where the averaged output becomes darker than it should be because the light pixels have less weight. In IrfanView, resampling and color profile conversions are done in 8-bit depth, so extreme adjustments to the gamma would yield banding.

I can't comment on the different appearance of raw images. It's typical that 3rd party software doesn't take some variable into account.

[Tsuwado]

Sorry to drop off like that. Yes I have the second option on too. I think I have the reverse of what you're thinking. I'm not seeing the noise normally and I'd like to. Now that I know what it is, why I can see it. I'm all set. I've got one machine so far that I'm only using for edit or computational work with images, that one will not have resampling on. Other machines I'll leave it on.

If anyone is interested, I've done some testing and like J7n stated, it's the resampling that is getting rid of the noise. IF you want to keep that, you have to resize with resampling, the closer you can get to the image being 100% sized at what you see, the better. I get it that the image is way smaller now but that's the trade off. Typically I'm at about only 30% of the image size. If you're sending to places like cell phones and Facebook, and you're viewing images on a 1080 screen, you'll be fine.

Outside of this, I have a image enhancement suite and one of them enlarges images. I'm finding with severe noise that it's doing better than the noise removal with the exported image. (As a complete aside to this, I could probably completely side step this if the complete mess of Adobe's DNG, wasn't such a mess)