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03/18/2002 01:13:37 PM · #1 |
I notice that quite a few images posted here are <25kb, and some that are less compressed show a lot of compression artifacts, so here's a simple (I hope) introduction to the twisted world of getting your pics to the web. I'm not a pro, nor do I play one on the web.
1. For starters, use the highest quality setting your camera offers when you shoot. Buy more memory if you need it. Imagine getting a once-in-a-lifetime shot that you can only make a tiny print of because it's so blocky. The bigger the original file, the more you've got to work with later. RAW and TIFF are great if you have them, but use at least the best quality JPEG setting and all the resolution you've got.
2. Do adjustments and editing (except for sharpening) on a COPY of the full-size image. Then downsize it to 640X480 at 72ppi (resample). This will smooth out most/all of the JPEG artifacts in the original image if you've got more resolution to begin with. Sharpen last, an don't overdo it.
Note: Keep the original file somewhere safe. It's your negative. Someday, when you've learned more about Photoshop (and you will, even if you know "everything" about Photoshop), you'll be able to go back and do it better.
3. If you use Photoshop, use the "save for web" feature. This not only applies .jpeg compression, but also reduces the colorspace of the image (probably SRGB) to match the available web palette. You can play with the settings yourself, or have the sw compress to a given file size. I don't want to put stress on the dpchallenge server, but go for broke here. 100kb is usually adequate, but the extra 50 won't hurt.
If you use Irfan View, ACDSee or another program you'll have to play with the "save" settings to get your image to the right size (maybe in "preferences"?), but, again, shoot for 100 - 150kb.
It's not all about the technicals, but you may as well take care of them as best you can.
Happy Shooting,
-Erik |
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03/18/2002 02:23:19 PM · #2 |
Excellent advice, this covers every step that's necessary to consistently produce a quality picture, and the proper order to do them! I'm not saying that an amazing picture couldn't be created without these steps but, on average, they'll save you a lot of headaches and give you better results.
Probably the most important (and subtle) of these tips is to do your shapening last. The apparent improvement that sharpening gives will vary wildly depending on output size and media... you should only apply it when you know exactly how your picture is going to be viewed, and after you've scaled it to the size you want. If you want to be really careful and have our image work well wherever you need to display it, don't save your master image with *any* sharpening, even if it's an extra copy of the original, cropped and levelled to your heart's content. Create the version you're going to display, *then* sharpen it.
Another trick for anyone with Photoshop is to crop the image to desired size and then, instead of applying Levels directly to the photo, you create a new Layer > Adjustment Layer > Levels. This will drop an editable 'Levels' layer in front of your photo that works just like the Levels control, but doesn't permanently modify the underlying image itself. This allows you to save an master version in Photoshop format that you can go back to at any time to tweak the Levels as if it were still right out of the camera. It's great for pictures that you want to show both online *and* print, since you don't always want the same Levels settings for each!
You can do the same sort of adjustment layers for other image adjustment tools (like hue and saturation) but those adjustments are against the rules, so I don't reccommend it. Even through I haven't been using it, a Levels Adjustment Layer is *probably* within the rules, since it's just a Levels, after all! :)
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03/19/2002 10:25:43 PM · #3 |
| Good point regarding sharpening and various output. As a rule of thumb, use larger radii (? Too lazy to drag out the Webster's) for print (1) and smaller for the web (0.6 - 0.2). I usually do two to three "doses" starting at a larger radius and working down for web stuff. |
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03/20/2002 02:51:13 AM · #4 |
I think I need to go back to school!! :o)
* This message has been edited by the author on 3/20/2002 2:52:28 AM. |
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03/20/2002 01:08:14 PM · #5 |
| I didn't learn any of this in school! I dredged it all up off the web and remembered the stuff that worked for me. :) |
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03/20/2002 08:30:34 PM · #6 |
| Jpegs are like old people...they deteriorate..kidding kidding. But serious, is it ok if you shot a pic in JPEG and saved it as a TIFF, would that stop deterioration? I can shoot in TIFFS but even with a 128 MB memory stick thats maybe 16 pictures and it takes forever to record if I have it set at 5 Megapixels. |
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03/20/2002 09:03:39 PM · #7 |
Once you compress to jpg, you get the jpg noise in the image... saving it to a TIFF afterwards won't take that compression away. That said, I'm certainly not saying take your photos in TIFF mode on your camera -- just take them at a decent compression.
When you're trying to figure out what compression to use for your submission to the site, I'd advise trying to find the threshold right above where you can see compression marks. You definitely don't want them in your picture, but you also shouldn't go with say 90% quality if you don't have to... because remember that people might be on slower connections. No need to torture them.
That said, quality comes first and will always beat my dialup concerns :)
Drew |
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03/20/2002 11:20:37 PM · #8 |
Don't sacrfice quality for dialup users. I use a free dialup service (so not one of the most reliable or fastest available) and the speed on the site is pretty bearable. I am on the west coast, and when I go in Sunday night at midnight EST, I can get through 70+ photos in 1-2 hours.
I'd rather see the image as you meant it to look, not with tons of artifacts from compression to make it faster for me. |
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03/23/2002 09:39:48 PM · #9 |
I sure wish I had read all of this before I submitted my first picture early this evening. I have much to learn.
And I was complaining about how long it took me to log my votes on the 77 pictures today. All of 30 minutes. Thank goodness for DSL. |
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03/23/2002 09:43:56 PM · #10 |
Don't forget you can unsubmit and resubmit your entry if you're unhappy with it!
Drew |
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03/24/2002 03:14:20 PM · #11 |
| Can I change the title without unsubmitting the picture? If so, how? |
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03/24/2002 03:41:28 PM · #12 |
| Not right now -- just unsubmit/resubmit. |
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03/29/2002 08:59:28 AM · #13 |
| Thank you all for the wonderful primer. I'm still trying to shoot a picture worthy of submitting. Looking at your work teaches me and challenges me. Now to work! |
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04/22/2002 06:24:17 PM · #14 |
I am a new DC owner, but have been a tech geek for way too long. Just wanted to point something out.
the rule of 72 DPI/PPI holds true on mac monitors, but the general number target for the PC is 96. You can save a bit of space with the 72, and it owuld be a subtle difference, but with so miniscule a difference in image size, you will really notice thedifference when viewing the pics on a windows machine.
Also, most of the Unix/Linux variants use the 96 flavor. The catch word has been 72 since the mac community long held sway over the print industry. But theirs is not the most accurrate representation many times.
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04/22/2002 06:58:10 PM · #15 |
I didn't think it mattered one bit what the dpi is. It has been my belief that where the web is concerned it is only the number of pixels (640 x 480 for example) that mattered. Dpi matters for print but is unimportant for a computer display. Isn't this correct? It has also been my belief that it does not matter how many times you open and close a jpg, it won't compress any further unless you make changes to the image and then resave and then the amount of compression is dependent on what changes you made. Am I correct on this as well?
Tim J |
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04/22/2002 09:14:40 PM · #16 |
opening and closing a file does not add loss.
As for the DPI/PPI, it effects the size it will display on screen. Example...
An image is 640X480, this much is finite. The color info and everything go in to make up the image, and lets say it is 100K. this will not change when the DPI setting is changed. The DPI setting is a reference point for screen rendering. If it is set for 72, it will print slightly larger than it will with a 96 setting. Heres why...
640 pixels across is our size. Divide this by our PPI to see how many inches across our image becomes.
640 / 72 = 8.88 inches across.
640 / 96 = 6.66 inches across.
Now there are 2 complications. The windows platform applies a basic 33% scale increase on everything on screen. From fonts to images it is all magnified, with the exception of images with a predefined PPI setting. Images without this setting will be scaled up like everytihg else.
And all of this is woefully inadequate when the image goes to rint, since it tries to directly convert PPI to DPI and makes for crappy images.
The only reason a monitor can hit decent appearance compared to the print equivalent, is due to the color control. A monitor can hit each pixel at exactly the color desired, where a printer has to use all those extra dots of resolution in halftoning techniques to simulate the colors desired. But a crisp black and white print can show which one truly has the cleanest edges.
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06/07/2002 06:40:52 PM · #17 |
I have been reading up on this alot lately, and the opinion I am getting for magazines like Shutterbug is: it is fine to shoot in JPEG, but but save the image in TIFF once it is on your hard drive. Everytime a JPEG,GIF,PNG, type file is saved it losses more information.
Also, for sharpening, what has worked best for me lately, is to sharpen first, then resize and compress.
Originally posted by Amateur Boy:
Jpegs are like old people...they deteriorate..kidding kidding. But serious, is it ok if you shot a pic in JPEG and saved it as a TIFF, would that stop deterioration? I can shoot in TIFFS but even with a 128 MB memory stick thats maybe 16 pictures and it takes forever to record if I have it set at 5 Megapixels.
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06/07/2002 07:46:08 PM · #18 |
Originally posted by timj351:
I didn''t think it mattered one bit what the dpi is. It has been my belief that where the web is concerned it is only the number of pixels (640 x 480 for example) that mattered. Dpi matters for print but is unimportant for a computer display. Isn''t this correct? It has also been my belief that it does not matter how many times you open and close a jpg, it won''t compress any further unless you make changes to the image and then resave and then the amount of compression is dependent on what changes you made. Am I correct on this as well?
Tim J
Your right here. DPI has to do with dots per inch when outputting onto paper.
PPI is the resolution at which you view images on a computer monitor.
Kind of simplified, but ...
* This message has been edited by the author on 6/7/2002 7:47:03 PM. |
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06/07/2002 11:22:20 PM · #19 |
This is all great advice - and advice I learned too late for my Games contribution. Oh well, I learned for it. One tip that I didn't see anywhere is: Take your photo in .jpg if you want, save as .tif to work on because you can save that one multiple times w/out degradation. Then do all your work as described above and save as .jpg right at the end.
These days, I keep the original out of the camera, save it as .tif, make changes (saving from time to time, sometimes multiple copies, then the last two steps are sharpen and converting to .jpg.
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06/07/2002 11:37:56 PM · #20 |
Good advice, I tried to convey that above, but you said it very clearly. I like to make most of the adjustments at full size, since some of the parameters are resolution sensitive. I feel it give a finer adjustment that way. That is just an opinion though.
Originally posted by gr8photos:
This is all great advice - and advice I learned too late for my Games contribution. Oh well, I learned for it. One tip that I didn't see anywhere is: Take your photo in .jpg if you want, save as .tif to work on because you can save that one multiple times w/out degradation. Then do all your work as described above and save as .jpg right at the end.
These days, I keep the original out of the camera, save it as .tif, make changes (saving from time to time, sometimes multiple copies, then the last two steps are sharpen and converting to .jpg.
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06/08/2002 12:15:39 AM · #21 |
I was under the impression that TIFF is a better format since it's uncompressed. Any reason to not set the camera to save TIFF files, other than space?
Mark |
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06/08/2002 12:56:25 AM · #22 |
Only space and the time it takes to save. If you can handle that, do it. The more info the better I guess. I have a 4 Mega pixel, and the JPEGs I save make rezor sharp 5x7's, in fact, they are too sharp for portraits. I have to do a lot of skin touch up. It takes about 10 seconds for my camera to save a TIFF, and for most of my stuff, I do not want to wait.
Originally posted by iggy386:
I was under the impression that TIFF is a better format since it's uncompressed. Any reason to not set the camera to save TIFF files, other than space?
Mark
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06/08/2002 12:59:59 AM · #23 |
Originally posted by Amateur Boy:
Jpegs are like old people...they deteriorate..kidding kidding. But serious, is it ok if you shot a pic in JPEG and saved it as a TIFF, would that stop deterioration? I can shoot in TIFFS but even with a 128 MB memory stick thats maybe 16 pictures and it takes forever to record if I have it set at 5 Megapixels.
I shot some TIFFs yesterday with my F707 and only got 8 of them on a 128mb stick...
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06/08/2002 02:01:17 AM · #24 |
Originally posted by Mousie:
You can do the same sort of adjustment layers for other image adjustment tools (like hue and saturation) but those adjustments are against the rules, so I don't reccommend it. Even through I haven't been using it, a Levels Adjustment Layer is *probably* within the rules, since it's just a Levels, after all! :)
Hue/saturation adjustments are within the rules.
It's nice to know that the way I generally work is the 'right' way :). I always sharpen at the end and do all my adjustments before scaling and so forth. If/when I get a better camera I'll have the right techniques to make the most of it :)
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06/08/2002 08:41:30 AM · #25 |
has anyone noticed that if you over-compress an image of anything to do with the beatles or john lennon, the compression artifacts seem to be spelling 'lucifer is our master'?
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