JPG Rejections - JetPhotos.Net Forums

Nigel Garrigan · 05-16-2012, 08:16 PM

Hi, I'd appreciate some help & advice as I've had a flurry of photographs rejected in the last couple of weeks, all for 'jpg artefacts'.

The photographs were all taken at the same time with the same camera settings (Fine & Large) as the 50 plus that are already in the db from the same trip to SXM, and the processing was also identical.

Having read some of the other threads in the forum it's kinda scarry with what's possible, as I only crop, clean, lighten & sharpen my shots, and I only use Picasa as my technical ability is pretty limited - sorry guys to be so basic.

I was fortunate enough to have my image down load increased to 1200px, and it seems that whenever I use that facility the jpg artefacts problem happens.

I've gone back to 1024, which is a shame as I like the shots in 1200, but I can't seem to get it right!

Any help, guidance & advice would be very welcome.

Thanks again.

Nig.

brianw999 · 05-16-2012, 09:32 PM

What camera do you use Nigel ?

Nigel Garrigan · 05-16-2012, 09:42 PM

Hi Brian, I have a Nikon D80 and a Nikon D60, I have a Nikon 70-300 lens attached to the D80 and a Nikon 28-135 attached to the D60. Both are set to Large and Fine settings. Hope that helps, all the best Nig.

brianw999 · 05-17-2012, 05:25 AM

Both good quality cameras so the problem has to lie in the processing.

I'm not familiar with Picasa and I'm at work at the moment so I can't download it (damn our IT department download blocks !).

Probably the most common way to introduce jpg artefacts is in saving at low resolution and/or saving an image multiple times. Each time you save you introduce a bit more compression (jpg artefacts).

Make sure that you save at the highest resolution available and only save the image once, at the very end of your processing.

I'll download Picasa and take a look at it's features and useage later at home.

Nigel Garrigan · 05-17-2012, 06:19 PM

Hi Brian, many thanks, any advice would be very much appreciated. All the best Nig.

Hinkelbein · 05-17-2012, 07:30 PM

Quote:

Originally Posted by brianw999

(damn our IT department download blocks !).

There are other reasons than Picasa for this, Brian

Nigel Garrigan · 05-17-2012, 08:19 PM

Hi, good news, would you care to share, as I can't seem to get the 1200px right. Many thanks, all the best Nig.

brianw999 · 05-17-2012, 09:47 PM

Quote:

Originally Posted by Hinkelbein

There are other reasons than Picasa for this, Brian

Absolutely...but I quoted the common reasons. Others include under / over exposure and trying to push the result to get a useable image. Another is using a small crop area of the image where the lens zoom maybe wasn't long enough to make for a large enough image.
Nigel,
It would help if you could post your workflow here to give us an idea of what you are doing.

Hinkelbein · 05-18-2012, 12:19 PM

In my early picture processing days, I had jpg artifacts when I resized the picture after having done all other steps. So nowadays, first thing I do is resize (to 1200, 1400 or 1600, depending on the picture's quality).

brianw999 · 05-18-2012, 04:34 PM

Quote:

Originally Posted by Hinkelbein

In my early picture processing days, I had jpg artifacts when I resized the picture after having done all other steps. So nowadays, first thing I do is resize (to 1200, 1400 or 1600, depending on the picture's quality).

Same here. My basic workflow is .......

1. Level original.
2. Crop to size.
3. Deal with any dust spots / small birds / out of focus flies.
4. Adjust histogram using the luminosity histogram.
5. Sharpen (overall and selective)
6. Final brightness / contrast adjustment.
7. Save at highest resolution.

Nigel Garrigan · 05-18-2012, 07:03 PM

Quote:

Originally Posted by Hinkelbein

In my early picture processing days, I had jpg artifacts when I resized the picture after having done all other steps. So nowadays, first thing I do is resize (to 1200, 1400 or 1600, depending on the picture's quality).

Hi, many thanks for your reply, I do what you used to do & resize after I've done everything else, so I'll change the process & resize first, although I've only got 1024 & 1200 available. Thanks for the tip & taking the time to reply. All the best Nig.

Nigel Garrigan · 05-18-2012, 07:13 PM

Quote:

Originally Posted by brianw999

Same here. My basic workflow is .......

1. Level original.
2. Crop to size.
3. Deal with any dust spots / small birds / out of focus flies.
4. Adjust histogram using the luminosity histogram.
5. Sharpen (overall and selective)
6. Final brightness / contrast adjustment.
7. Save at highest resolution.

Hi Brian, many thanks for your advice, and the process you follow with your photographs. I follow a similar work flow as you except I'm not sure what the luminosity histogram is ( I just follow the histogram presented in Picasa) and I resize after the processing. I also think I've been too ambitious with submitting shots when the zoom on the camera could have been used to better effect.
Many thanks again for the tips - which I'll follow, and taking the time to reply & help.
All the best. Nig.

Nigel Garrigan · 07-30-2012, 07:38 PM

Quote:

Originally Posted by brianw999

Same here. My basic workflow is .......

1. Level original.
2. Crop to size.
3. Deal with any dust spots / small birds / out of focus flies.
4. Adjust histogram using the luminosity histogram.
5. Sharpen (overall and selective)
6. Final brightness / contrast adjustment.
7. Save at highest resolution.

Hi Brian, followed your advice to the letter & for a while all was well, so many thanks for that, but now the same old problem is reoccuring, and I'm not sure why. These images are taken at the same time, with the same equipment & processed & compressed in the same way - using the method you suggested, and yet there is now a phase of jpgs rejections - I can't see the jpgs on my screen - if I could I wouldn't submit the image - not sure where to go from here. Once again any help & advice would be much appreciated. All the best Nig.

brianw999 · 07-30-2012, 08:16 PM

^^^
Could you post a couple of examples ?

Nigel Garrigan · 07-31-2012, 08:04 PM

Hi Brian, thanks for any help & advice you can offer. On my equipment I'm struggling to see the difference between images that are accepted & those that are rejected as jpgs, they look very similar. This image was rejected for jpgs & undersharpened, and I don't think Picassa caters for sharpening parts of images - it's all or nothing. Thanks again Nig.

akerosid · 10-05-2012, 08:00 PM

I've also had problems with compressions artefacts recently and this thread has given me some very useful pointers.

I would like to work on some of the photos that I had rejected and try out the methods Brian has listed above.

My methodology is generally as follows:

1. Level (if applicable)
2. Crop
3. Brightness/contrast (yes, I do use those!!)
4. Sharpness
5, Reduce to size and save in folder.

I see that I'm going to need to amend this. However, when I'm asked to save, I always save in the highest quality available. I will try working on some of the photos that were previously rejected and post them first before submitting again.