RAW files to get printed and posted here

[christophertravels]

I have taken the plunge and bought myself my first DSLR, a Canon XTi. I've been using a P&S for three years, and I know it's limitations. Although I can take fairly good photos, I think I reached my limit with the P&S.

So now I can take RAW images. I know RAW is 16 bits, and JPEG 8 bits. But what happens when we convert to JPEG to post our photos here online? Is all that data lost / compressed to make 8 bit data? Can you tell the difference between a photo taken originally in JPEG or RAW here online?

And what about printing? If I send my images off to be printed by my local photography merchant, who wants JPEG images, then is all that data lost / compressed?

(I searched and couldn't find the answers to my specific questions about RAW, I hope someone can help)

[dang]

I'd suggest checking these sites for some helpful info:
http://www.normankoren.com/sitemap.html
http://www.rideau-info.com/photos/index.html

[ghsmith178613]

I have taken the plunge and bought myself my first DSLR, a Canon XTi.

Did your camera come with a software cd? Did you install same? Did part of the suite come with Digital Photo Professional 2.2? This is a file manager and RAW processing program.

I've been using a P&S for three years, and I know it's limitations. Although I can take fairly good photos, I think I reached my limit with the P&S.

I wonder which version of Photoshop? Photoshop CS2 has a RAW image processing program in it. PSCS2 also has a sophisticated file manager. PSCS3 is in final beta testing. I simply don't understand how, "I think I reached my limit with the P&S." Are you an Adobe Certified Engineer?

So now I can take RAW images. I know RAW is 16 bits, and JPEG 8 bits. But what happens when we convert to JPEG to post our photos here online? Is all that data lost / compressed to make 8 bit data? Can you tell the difference between a photo taken originally in JPEG or RAW here online?

RAW is the current "film quality" file format. RAW is unprocessed data. When you open these images in the processing suites, the prompts will allow you to convert to any of the popular file formats. You will still have the RAW files unless you do something deliberate to delete them.

And what about printing? If I send my images off to be printed by my local photography merchant, who wants JPEG images, then is all that data lost / compressed?

Digital Photo Professional 2.2 and Photoshop CS2 have printing software in them. Additionally, when you process you images and save them, you have the choice to save them in 8 bit or 16 bit, and target them to any of the color spaces any other printing service could require.

(I searched and couldn't find the answers to my specific questions about RAW, I hope someone can help)

I hope this make things easier for you.

ghsmith178613
assoc. prof. photo technology
Canon XT
PSCS2
(candidate) Adobe Certified Instructor
Epson 2200
Epson 2800
Epson 7200

[jimgephart]

"I wonder which version of Photoshop? Photoshop CS2 has a RAW image processing program in it. PSCS2 also has a sophisticated file manager. PSCS3 is in final beta testing. I simply don't understand how, "I think I reached my limit with the P&S." Are you an Adobe Certified Engineer?"

I believe they were referring to P&S as a point and shoot digital camera and not PS - Photoshop. Thus the finding the limitations of the camera and stepping into a DSLR.

[jimcritchley]

Basically, shooting in RAW allows you to post-process in any software without losing data. The last step before printing should be your conversion to jpeg, I have not seen anywhere that can print RAW files although I may be wrong here. However, you can convert to TIFF which is another no loss data format and print out your pictures. Hope this helps.

[maresphotos]

This is not very technical, but you can compare raw to a negative that you get when you shoot film, in that it has to be developed before it can be printed or viewed. The software that you use, like Adobe Camera Raw or Canon DPP, is the lab that developes it. You decide what data you want to keep and the rest is not used.

If you are concerned about losing data, convert from raw to tiff. Work on the tiff file and when you want to print, convert the tiff to jpg. The print image will look just as good as the tiff or jpg.

The main advantage of raw is that it gives you a wider range of data to work with when converting to jpg. This means it is easier to correct for under or over exposure, easier to correct white balance, and other adjustments. When you shoot jpg, the camera does the developing for you, then throws away the un-needed data. When you shoot raw, you make the decisions yourself, using all the data, then you throw out the data you don't need when you convert to tiff or jpg.

I have seen examples of the same image that was taken raw and then taken jpg. The raw was converted to tiff for post processing. The same post processing was applied to each image. When compared side by side the one that was shot raw looked slightly better, but there was nothing wrong with the jpg. It just depends on how much post processing you want to do, or how much of a perfectionist you are about your images.

[andrys]

If you are concerned about losing data, convert from raw to tiff. Work on the tiff file and when you want to print, convert the tiff to jpg. The print image will look just as good as the tiff or jpg.

Just wanted to point out that you'd want to print from the tiff file image
(if your software can do that), since the jpg will be compressed a LOT to
get that smaller file and will result in loss of data with addition of artifacts.

If you print just after converting from tiff to jpg but haven't closed
the file on your editor yet, the image will be the one from the tiff file, so
that'll be ok. But if you close the file and open the jpg and print from that
you'll print an inferior version.

[reflectionsbyruth]

Glad to see someone else saying printing from 16bit tiff comes out much better

[jellophoto]

In answer to to your questions

Yes you do lose data when you convert to jpeg. Really you should only convert a file to this format for web posting due to the compression and artifacts caused by the process. I know many people print from JPEGs and for snaps and home use it is OK. For any high quality printing, especially at A4 size and above I would only do it if I had no other option. Preferable to save in TIFF or a native file format such as PS, as you can save all your post processing info. Converting to JPEG will throw all that away and compress the image, throwing yet more data away.

Make sure you have an original file saved in whatever format you started with (RAW or otherwise).

Do not edit in JPEG or you will degrade your file every time you save and lose the quality you started with.

Online you can only post jpeg and it is the end result of a process. If you shoot RAW then you will have to go through a series of processes to get to your jpeg upload. What you see on the monitor is a lower quality than what you print.

Can you tell the difference between a photo shot RAW, then processed to JPEG, or one that is shot and saved in camera in JPEG?- Possibly, but not necessarily. It depends on the amount of control and post processing you apply to the image. It is a little subjective.

You will see a difference between the two once they are printed, especially if you have post processed the RAW image, adjusting the image to bring out the best.

It really all depends on what you want to achieve.

Regards John