Experimenting with RAW

[aam1234]

Posted this thread in PP&Printing forum but though it might be suitable here too.

http://photography-on-the.net/forum/showthread.php?t=37410

Thanks

[DaveG]

Posted this thread in PP&Printing forum but though it might be suitable here too.

http://photography-on-the.net/forum/showthread.php?t=37410

Thanks

The RAW file size is correct with a 6 (ish) MP size. Photoshop CS makes the RAW a 18 meg (@ 8 bit depth) .psd file, or a 32 meg file when I choose to make it 16 bit depth. The jpeg size is obviously anything you want it to be.

Although my workflow is in transition (whose isn't?), I am trying to be careful with disk space. I'll decode the image and almost always save it as a Photoshop (.psd) file, where I do all of the work to the image. Then I'll flatten the image and save it as a jpeg of the size that the client requires.

If the assignment is fairly straitforward - say the bunch of H&S shots that require no layers or corrections; then I'll go from RAW directly to jpeg. When it comes time to save to CD I'll save whatever I have but as it also goes on another large hard drive and then I'll delete the .psd files. For routine stuff I figure that I can always go back to the RAW if I need to, and I'd like to get rid of all these 18/32 meg files.

[MRCPhoto]

All this technical terminology and data. Sigh....I always feel like such an itiot trying to understand it all.
Meesha

[DaveG]

All this technical terminology and data. Sigh....I always feel like such an itiot trying to understand it all.
Meesha

RAW is a compressed file (and that compression comes as a surprise to a lot of people) with almost no camera induced parameters. There isn't any white balance for example so you can do this later. RAW is about as pure a file as you can get.

.psd is the native Photoshop file. With this kind of file there is no compression. If you have a 6 megapixel camera (and you do if you have a 10D or a dRebel) you multiply the megapixel number by three (to get red/blue/yellow) and get 18, and that's the size of the fully blown up file in megabytes: 18 Meg.

Now you can use a RAW file in a couple of ways. You can have Photoshop CS (and other conversion programs) "decode" it at 8 bit depth. That makes the 18 meg file mentioned above. Or you can have it decoded in 16 bit depth. This makes a 32 megabyte file but the huge advantage is that you get many many more shades of colours. So tweaking colour should be smoother.

jpeg is a file type that compresses information and is said to be "lossy" which means that you lose some information when you save. After tens of saves of the same image you might see some damage. As a matter of workflow most people will work with a .psd or .tif file, do all of the corrections and then save it, as the last thing they do, as a jpeg. jpegs are great for sending over the internet as the file sizes are much smaller.

.tif is similar to a .psd file in the way that it's not compressed and you can use Photoshop layers and such with it. It tends to be a more universal file system so that non Photoshop programs are going to be more likely to
"see" the image, while they may not "see" .psd's. I don't use tiffs much since I just think that they are redundent to Photoshop files most of the time.

[Danny Boy]

One advantage .tif files have over .psd files is in the processing of pictures at some retail stores. I once brought my CF to a Walgreens for the printing of some pictures and I had them in a .psd format. Walgreens, and I assume other retailers, could not accept that format but when I brought the pictures in a .tif format, they were able to process the prints.