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DPChallenge Forums >> Current Challenge >> 150 K ruins the photo
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 03/16/2007 06:32:20 AM · #1
I just had to save my entry for multiple lightsources. But to bring it down to 150 k completely ruins it. it looks like crap now :(

not that it's a ribboner or anything, but I would like it to show up as normal quality photo.
 03/16/2007 06:51:00 AM · #2
Resize the image slighty smaller so you can gain some of the quality back (I assume the quality of the jpeg is below 70ish?

03/16/2007 06:54:30 AM · #3
Originally posted by Puckzzz:
I just had to save my entry for multiple lightsources. But to bring it down to 150 k completely ruins it. it looks like crap now :(

not that it's a ribboner or anything, but I would like it to show up as normal quality photo.


You must be doing something wrong then. What do you use to resize and save?
 03/16/2007 06:58:34 AM · #4
I know what you mean. I had the same thing for the grain image...it was up to '250k'...I had to cut it up a little and save it at very low quality...luckly it's image grain contest...so you don't see that much that is loooow quality (thank you grain and noise :PPP)
 03/16/2007 07:10:51 AM · #5
I use the 'save for web' option in PS CS2. have to set it to 78 or something :{
 03/16/2007 07:13:11 AM · #6
Using CS2 you should have no problem saving at 150K. You don't need to be at 78 for it to look good. Take it down all the way to 60 or use the optimize to file size option and set it at 150k.
 03/16/2007 07:18:38 AM · #7
ahhaaaa, I should try that too
 03/16/2007 07:54:21 AM · #8
I use the optimize to file size option set at 150k and have never seen a difference in the quality. There's a tutorial here called "Using Photoshop to Prepare Photos for DPC Challenges" and it shows you how to do that.
 03/16/2007 08:06:11 AM · #9
The most important thing I've found, is to resize the image to its final dimension, THEN save for web. Say the longest side for a challenge is 640 pixels. In PS, go to
(Sorry if this is too basic for many people, but I'm sure SOMEONE will find it useful...)
 03/16/2007 08:20:11 AM · #10
Originally posted by Puckzzz:
I just had to save my entry for multiple lightsources. But to bring it down to 150 k completely ruins it. it looks like crap now :(

not that it's a ribboner or anything, but I would like it to show up as normal quality photo.

Are you saying it's ruined because the quality is bumped down to the 70's, or that it's ruined because it's full of visually obvious jpg artifacts?

I've saved photos at jpg qualities far lower than 70 and found them to be visually indistinguishable from much larger files.
 03/16/2007 08:29:05 AM · #11
On the heels of my previous message, here is my now-famous photo compression test. Each of the below photos is compressed at VERY DIFFERENT jpg levels. Open each photo in a different tab (assuming you're using a tabbed browser) and don't cheat. Don't look at the properties to see what file is high quality and what is low. Do a pure visual inpsection. Can you tell the difference?



After making your picks, open the link below to see the file sizes/qualities.

Answer
 03/16/2007 08:46:03 AM · #12
Try stepping the file size down a little at a time until you reach the desired size. I read this in a thread somewhere here, and it works well for me. I resize about 4 or 5 times in even steps, until the final 2, then do them 1/2 and 1/2 (ex; reduce it about 20% at a time until it is about 850K, then step 350 and 350 to reach the 150 number.)
For a contest entry, it helps to also take out all the extra info files that ride with the pic, which leaves more space for the actual image file.

Message edited by author 2007-03-16 08:48:39.
 03/16/2007 09:53:24 AM · #13
Originally posted by strangeghost:
On the heels of my previous message, here is my now-famous photo compression test. Each of the below photos is compressed at VERY DIFFERENT jpg levels. Open each photo in a different tab (assuming you're using a tabbed browser) and don't cheat. Don't look at the properties to see what file is high quality and what is low. Do a pure visual inpsection. Can you tell the difference?



After making your picks, open the link below to see the file sizes/qualities.

Answer


the first is way better quality,the second one is very poor, the third is a little better but not as good as the first. and by looking at the anwser afterwards I was right :)
 03/16/2007 09:59:24 AM · #14
Originally posted by Puckzzz:
Originally posted by strangeghost:
On the heels of my previous message, here is my now-famous photo compression test. Each of the below photos is compressed at VERY DIFFERENT jpg levels. Open each photo in a different tab (assuming you're using a tabbed browser) and don't cheat. Don't look at the properties to see what file is high quality and what is low. Do a pure visual inpsection. Can you tell the difference?



After making your picks, open the link below to see the file sizes/qualities.

Answer


the first is way better quality,the second one is very poor, the third is a little better but not as good as the first. and by looking at the anwser afterwards I was right :)


me too, me too :)

but I don't see the point of this "exercise" :/
 03/16/2007 10:06:02 AM · #15
well I would like the point to be that the allowed image size could be a little bit higher. Something like 200 or 180 K, would be an improvement.
 03/16/2007 10:12:02 AM · #16
Originally posted by Puckzzz:
Originally posted by strangeghost:
On the heels of my previous message, here is my now-famous photo compression test. Each of the below photos is compressed at VERY DIFFERENT jpg levels. Open each photo in a different tab (assuming you're using a tabbed browser) and don't cheat. Don't look at the properties to see what file is high quality and what is low. Do a pure visual inpsection. Can you tell the difference?



After making your picks, open the link below to see the file sizes/qualities.

Answer


the first is way better quality,the second one is very poor, the third is a little better but not as good as the first. and by looking at the anwser afterwards I was right :)


Funny that the 1st and 3rd are more than 150k.
The one the that could be entered, 2nd one, looks ok but not nearly as good as the other two.
Does this support upping the size then? ;)
 03/16/2007 10:15:05 AM · #17
This happens to me alot, Especially with photos that contain alot of texture. Brick Buildings are the worst.
 03/16/2007 10:23:36 AM · #18
John's test is a very good illustration of the "diminishing returns" of increasing file size. His source photo is a difficult-to-compress image because it contains lots of fine detail. The only thing really missing is an area of smooth tonal change to show JPEG artifact along edges and effects on slow tonal shifts. It's a great illustration, nonetheless. There *are* differences, particularly between the original and the 76k "highly compressed" image. Doing a "difference overlay" will show them. Place the 76k image on a layer over the 644k image, and set the blend mode to difference. Bottom line, the differences are subtle, and unless you go looking for them, and have the original for comparison, they will not be readily apparent. As file size is increased above 150k, the differences become so small as to be negligible, for the vast majority of images. I've had a couple images that I have had trouble getting to 150k while maintaining best possible quality, but again, I'm looking at them very critically, and comparing to the original, which the voters will not be able to do, nor will they take 5 minutes to examine the minutiae of the image.
For the 640Px image size, the 150k file size is quite appropriate. For the 720Px image size, 200k is more appropriate (190k would match the "bits per pixel" information content of the 640Px size).
 03/16/2007 10:24:09 AM · #19
Here we go again beatin the same dead horse.
 03/16/2007 10:27:43 AM · #20
Originally posted by NstiG8tr:
Here we go again beatin the same dead horse.


It may seem like a dead horse, but remember that many folks have not been party to earlier discussions. For reference, there are of course multiple historical threads on this... I'll leave it to others to research them, they cover several years.
 03/16/2007 10:38:13 AM · #21
About 1 out 5 images I take for a challenge I don't enter because of compression artifacts. If I could change just one thing about this wonderful site it would be to increase the limit to 200k. My average setting using PS's save to web is about 65. IMO it really limits some detail oriented styles of photography, and favors some bold graphic (DPC) styles. Just my $.02.
 03/16/2007 11:28:31 AM · #22
Just to show what we're all up against:



This shows the resulting file size when various JPEG "Quality" settings are selected, using John's 644kB "original" of the dog. Notice how you can get 150k @ about 55 quality, but going to 200k only gets you to 67 quality. Even 300k only takes you to 78. That's double the file size, for very little real gain in *visible* quality.
 03/16/2007 11:36:25 AM · #23
Sharpening also makes files larger at a given quality setting. Unfortunately, voters penalize soft images. You can also do a monochrome conversion to get high quality settings.

The grain challenge is, of course, a real *challenge* in this respect since the more detail in a JPEG image (and grain is detail) the larger the file size.
 03/16/2007 11:44:48 AM · #24
In my previous entries it hasn't been a huge problem, although it did look better with a higher quality. but for some reason the photo I want to enter now has hardly been postprocessed and still comes out at nearly 300k after resize. So when I have to take that down to 150 I loose a lot and get a lot of artifacts.
 03/16/2007 11:53:32 AM · #25
Try a bit of very gentle noise reduction. If it's for a Member Challenge, try running the noise reduction on selected areas where it will be less noticeable.
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