Processing RAW and JPEG in ACR

[Walshy]

I wonder if someone could explain what the difference to the end result would be if I was to process the same image as a JPEG and Raw in ACR. I currently Brouse in Bridge and then open the selected shot in ACR. Once I have made the desired adjustments using the sliders in ACR I then open the image in CS4 and then save. When PPing in ACR there doesn't seem to be any difference to the way it handles JPEG or RAW images and no appreciable difference to the resulting image. My question would be if this is the case what then is the advantage to shooting in RAW.

[pwnage101]

If I understand correctly, RAW files are merely images with a bit depth greater than 8 (typically 12 or 14), whereas JPEG is 8-bit. Also, because RAW images are recorded image sensor data, they don't have gamma correction applied. Together, a combination of "untouched" data and higher bit depth allow for more accurate images after making edits. As you have already noticed, this added accuracy is hard to see if the changes are minor. RAW images are mostly beneficial for major alterations to the image. This is crucial for HDR imaging and perfectionists like myself

[carregwen]

A Jpeg starts it's life as a RAW file. All files start as RAW. The camera captures all of the data (as a RAW) but if you have set the camera to JPEG mode the camera processor will produce a processed JPEG from the data, based upon your camera settings. The data that isn't needed from this Jpeg is junked - hence the smaller data files for Jpeg. The file is also internally compressed to keep the size small. If you then edit that jpeg you have much less data for the editor program to work with, so you get more distortion in edit, and you are less able to make significant changes in edit. If you make repeated edits with a jpeg, you lose a little bit more data each time you save it. This doesn't happen with a TIFF or PSD file saved in CS from a RAW.

If you have the time, then RAW is best. You can set up pre-set profiles in CS and other applications that speed up the processing. You will end up with better quality images with RAW.

[Colin Southern]

Hi Walshy,

I'm not sure if I'm understanding you correctly - are you asking "what's the difference between processing a RAW file with ACR -v- processing a JPEG file with ACR"?

[carregwen]

I thought he meant processing a jpeg in RAW. That's why I mentioned the deterioration cause to a jpeg in any edit program.

[Terry Tedor]

In addition to the benefits Rob mentions, processing as a RAW and then converting to JPEG allows YOU to control that conversion process instead of relying on the camera manufacturer's firmware to make the decisions for you.

[carregwen]

In addition to the benefits Rob mentions, processing as a RAW and then converting to JPEG allows YOU to control that conversion process instead of relying on the camera manufacturer's firmware to make the decisions for you.

Quite right. It's a bit like using cruise control on the wife's Ferarri.....?

She had a Peugeot last time I looked.

[Colin Southern]

I thought he meant processing a jpeg in RAW. That's why I mentioned the deterioration cause to a jpeg in any edit program.

That's the bit that's confusing me.

@ Walshy - RAW and JPEG are mutually exclusive; although from CS3 onwards one can open a JPEG with ACR, it's not doing "the full Monty" (no demosaicing and gamma correction etc) so although controls like fill light still try to work, it's only "going through the motions" with what it has to work with which will be far far far short of what it would have had if the file was a true RAW file.

JPEGS are all geared up to be the smallest size possible - and one of the ways it does that is by throwing away data* that the human eye can't see anyway - like detail buried in the shadows.

* with a modest safety margin to allow for differences in monitors and the possibility of small adjustments.

[Walshy]

Hi All
Thanks for the explainations I think I understand a little more about the differences between JPEG and RAW. Having said that could someone give me a typical work flow when working in ACR. As you guys are aware there are a great many sliders and I am sure that one doesn't have to make adjustments to all of them to get the final result.

[carregwen]

Hi All
Thanks for the explainations I think I understand a little more about the differences between JPEG and RAW. Having said that could someone give me a typical work flow when working in ACR. As you guys are aware there are a great many sliders and I am sure that one doesn't have to make adjustments to all of them to get the final result.

I don't really think there is an answer to that. I'm finding that I'm developing a style of images, and that manipulating the controls in ACR (CS4) in a certain way helps me get the result that I want. It really depends on the type of shot and what you want it to look like. I use high contrast and strong colours colours for a lot of my shots. But others may do quite the opposite. I would suggest you decide what 'look' you want, then try to get as close to that as possible in camera when you shoot, and then find the best control adjustments in ACR to finish it.

You can spend too long on the PC you know...

[Walshy]

Thanks Rob
Your right you can spend too long on the computer.
Walshy

[Terry Tedor]

Hi All
Thanks for the explainations I think I understand a little more about the differences between JPEG and RAW. Having said that could someone give me a typical work flow when working in ACR. As you guys are aware there are a great many sliders and I am sure that one doesn't have to make adjustments to all of them to get the final result.

As mentioned in this thread, you might want to consider picking up the excellent book mentioned by Dave Humphries, "Real World Camera RAW with Adobe Photoshop CS4". It explains in great detail the benefits of shooting RAW and what each control does in ACR.

[Colin Southern]

could someone give me a typical work flow when working in ACR.

In a nutshell (and please don't think that I'm being sarcastic) but in my opinion it's simply a case of starting at the top and adjusting each slider to make the image look better - and then repeat. You'll seldom need to use the other tabs. After a while you'll learn to spot things like needing a higher black clipping point, or less brightness (and you may want to "get in the ballpark" by dealing to those issues first), but ACR converts the entire image in one pass regardless, so from a technical point of view it doesn't matter what order you do things in - just whatever you find easiest for you.

[Walshy]

As mentioned in this thread, you might want to consider picking up the excellent book mentioned by Dave Humphries, "Real World Camera RAW with Adobe Photoshop CS4". It explains in great detail the benefits of shooting RAW and what each control does in ACR.

Sounds good I will look for it
Thanks

[Walshy]

In a nutshell (and please don't think that I'm being sarcastic) but in my opinion it's simply a case of starting at the top and adjusting each slider to make the image look better - and then repeat. You'll seldom need to use the other tabs. After a while you'll learn to spot things like needing a higher black clipping point, or less brightness (and you may want to "get in the ballpark" by dealing to those issues first), but ACR converts the entire image in one pass regardless, so from a technical point of view it doesn't matter what order you do things in - just whatever you find easiest for you.

Thanks Colin. That's basically what I have been doing. However when you talk about needing a higher black clipping point, is that achieved by moving the "Blacks" slider to the right?

[Colin Southern]

Thanks Colin. That's basically what I have been doing. However when you talk about needing a higher black clipping point, is that achieved by moving the "Blacks" slider to the right?

Yes. Every image normally has "something black" and "something white" and "everything else inbetween" so that the image uses the full spectrum - but - an image that technically meets these requirements may have black or white areas that are too small for the brain to register and (in basic terms) it "just looks better" if you bring the clipping points further (especially when printing).

Just to be clear though - using ACR on a RAW file has the potential to get you a MUCH better image than using ACR on a JPEG (especially if the image needs rescuing with large level shifts).

[Walshy]

Thanks Colin
That makes it much clearer. I will shoot in RAW more often and look forward to better results.
Thanks
Walshy

[Terry Tedor]

Good luck! I think you will be very pleased with the results. It may take a little more time to work with each image than you're used to but the results are definitely worth it.