4 Replies Latest reply on Jul 16, 2009 5:10 PM by A.Sylvain

    A few questions about bit channel

    A.Sylvain

      In the workflow options with Camera RAW 4.6, which bit channel should I select when working on a RAW file? 8, 16 or 32.

       

      Is it depending on which camera you use?

       

      So far the only differences I have noticed between each of them is the lower the bit, the smaller the file size in tiff format. And the lower the bit the more options become available with Photoshop CS3 filters. As well, a 16 bits tiff file needs to be converted into 8 bits to save as JPEG.

       

      To this day, as I do not use much of the filters, I've always selected it at 16 bits and then opened my files with Photoshop CS3 for a few touch ups and then save them into tiff.

       

      Am I doing that right?

       

      Also, I've recently stared to play around with artistic filters in Photoshop CS3 so I had to convert them into 8 bits before wards and then I saved them as tiff. Can I convert them back from 8 bits to 16 bits or higher?

       

      Is there anything else I should know about bits that is important?

       

      Thanks,

       

      Sylvain

        • 1. Re: A few questions about bit channel
          Ramón G Castañeda Level 4

          A.Sylvain wrote:

           

          In the workflow options with Camera RAW 4.6, which bit channel should I select when working on a RAW file? 8, 16 or 32.

           

          Is it depending on which camera you use?

           

           

          No. It depends on your intended workflow, what you plan to do to and with your files, and how well you know Photoshop.

           

           

          Here's some essential reading for you [click here].

          1 person found this helpful
          • 2. Re: A few questions about bit channel
            Bill_Janes Level 2

            A.Sylvain wrote:

             

            In the workflow options with Camera RAW 4.6, which bit channel should I select when working on a RAW file? 8, 16 or 32.

             

            Is it depending on which camera you use?

             

            I haven't worked with ACR 4.6 for a while, but the only options available in the Workflow Options with the current version are 8 or 16 bit. 32 bit floating point is available in Photoshop and is for HDR (high dynamic range) work. If you are using aRGB or sRGB and edit the images in ACR rather than in post processing, 8 bits is usually adequate as this bit depth with a gamma of 2.2 is sufficient to encode what the eye can see. If you make significant changes in the tone curve in post processing, then you might want to use 16 bits.

             

            If you use ProPhotoRGB, you should probably use a bit depth of 16. However, since you appear to be a beginner, I would not advise that you use ProphotoRGB. I agree with Ramon that the book by Fraser and Schewe is essential reading.

            • 3. Re: A few questions about bit channel
              A.Sylvain Level 1

              Thank you very much Ramon G Castaneda for your reply and the link on the Camera Raw with Photoshop ,

              • 4. Re: A few questions about bit channel
                A.Sylvain Level 1

                Thank you very much Bill_Janes for your reply,

                 

                You are right ACR4.6 workflow only contains 8 and 16 bits my mistake.

                 

                So far I've only worked with sRGB, but from what I understand, I will keep working with 16bits as I do use the curves preset settings in post processing with PS3 Layers. I often use the linear contrast or the lighter RGB as a base then adjust it according to the image. I also use the layers levels and color balance.

                 

                As you guessed well, I'm still a beginner, and I've noticed recently that I've done a lot of mistake while processing my images such as black and white points color balance etc...I've just recently learned about these things.

                 

                Cheers,

                 

                Sylvain