Getting red and black pixels in Photoshop but not in Lightroom

[final cut cafe]

I have an image I wish to print, but at 100% view in Photoshop CS2, I see red and blue pixels scattered

throughout the image. When I load the exact same image in Adobe Lightroom, I only see those pixels for

the first two seconds while the image is loading, then they disappear. They don't disappear in

Photoshop, even if I move around in the picture.

 

Why is it I am seeing these pixels in Photoshop but not in Lightroom? Will these pixels be visible in my

final print?

[j_woo]

I'm guessing here, but the red and blue pixels are most likely hot pixels (areas of charge

leakage on your camera sensor). Hot pixels are usually more noticeable in long exposures

and high ISOs.

<br><Br>

Assuming you are viewing some sort of RAW file format, Lightroom (and Adobe Camera

Raw) will map out these hot pixels automatically. If you've opened a raw conversion from a

different application that does not map hot pixels (for instance, the current version of

Aperture), you will see those hot pixels.

<br><Br>

You're the best one to answer whether or not the pixels will be visible in the final print --

maybe yes, maybe no. Depends on your print size, the number of dead pixels, and the

region affected. Naturally, large areas of flat color will show hot pixels more obviously.

[final cut cafe]

Yes, I did use a long exposure of 4 seconds, but I don't understand why they are not visible

in Adobe Lightroom. Well, they are while the image is loading, but after that the view is

clear at 1:1 without any hot pixels. The same image in Photoshop shows them at 100%.

How noticeable are hot pixels when printed on a Frontier or Lightjet system?

[final cut cafe]

sorry, I didn't read your entire response before I wrote my previous comments. I am in fact

viewing RAW images in Lightroom, then a TIFF in Photoshop. How can I keep the image

"mapped out" and export to TIFF or JPEG?

[final cut cafe]

ok problem solved! What I was doing is viewing the images in Lightroom, then opening the

RAW files up directly in Autopano and creating my panoramic. Then opening the big image

in Photoshop. With that workflow, I was seeing the hot pixels. I tried exporting from

Lightroom TIFFs and they all look clean! So I will send those TIFFs into Autopano.

[alec_myers]

Just out of interest, see if you've got the default chroma noise reduction still switched on in Lightroom - it's usually set at 25 (out of 100) and whether that makes a difference

[final cut cafe]

Alec,

 

Yes in deed, noise reduction was at 25. Is this good or bad?

[glenbarrington]

IS NR good or bad? Depends on what you are going for. NR works by blurring the image just a bit, so NR that is too strong will cause you to lose detail in a way that may be unacceptable. But in a noisy image, the noise can get in the way and distract the viewer.

 

Finding the balance is the key and that is mostly a personal taste thing. Sometimes in some photos, you can never find an acceptable balance.