19 Replies Latest reply: Dec 16, 2013 10:26 PM by JJMack RSS

    Dramatic drop in file size - please help?

    Maddiex Community Member

      My CR2 files of about 25MB are being reduced to about 1MB jpg's after going through ACR and PS CC and being saved. Sometimes I crop and sometimes I don't, this is not the reason.  Also I choose the save as max file size always. Where am I going wrong?

       

      Mac OSX 10.6.8

      PS CC

      Using Bridge

        • 1. Re: Dramatic drop in file size - please help?
          c.pfaffenbichler Community Member

          Do you have an idea what jpg is and does?

          Destructive compression can achieve steep reduction in size – albeit at the prize of damaging the image.

          • 2. Re: Dramatic drop in file size - please help?
            JJMack Community Member

            Actually there has been an increase in file storage space, You now have a 25MB CR2 Raw file and a 1MB jpeg file when I went to school 25+1=26MB... Then theirs is that ACR data if you used ACR to concert the mosaic file into a RGB file you has an additional sidecar file or ACR database entry for your RAW file. You have increase storage requirements and not gained any back.

            • 3. Re: Dramatic drop in file size - please help?
              Curt Y Community Member

              JPEG is a lossy format, meaning each time you save it recompresses the image.  Probably would not notice the for many cycles unless you are going to print at 11x17 or larger format.  If you saved at jpg 10 quality you probably would not see any difference, but the fle size drops considerably.

               

              If you want max quality save as psd or tiff.

              • 4. Re: Dramatic drop in file size - please help?
                Maddiex Community Member

                I understand some loss is inevitable but I used to go from 25MB to about 11 or 12 MB in the save now I am going to 1MB and sometimes even half of that. It is clearly some setting I have changed?

                • 5. Re: Dramatic drop in file size - please help?
                  Curt Y Community Member

                  There is not fixed conversion rate.  How much compression occurs depends on the image.  Less compression can occur with a complex image as opposed to one with a lot of the same, like a clear sky.

                  • 6. Re: Dramatic drop in file size - please help?
                    Maddiex Community Member

                    I understand thank you but there has been a huge drop across the board in my file sizes?

                    • 7. Re: Dramatic drop in file size - please help?
                      Curt Y Community Member

                      Try a test then and report back.  Take image xxxx and convert in old PS program at jpg 12  quality and 10 quality.  Then use same image and do with CC.

                      • 8. Re: Dramatic drop in file size - please help?
                        JJMack Community Member

                        Maddiex wrote:

                         

                        I understand thank you but there has been a huge drop across the board in my file sizes?

                        Perhaps some day you will understand that the only rgb image you have in your 25MB raw file was s poor scaled down jpeg preview image which is much lower in image quality then the one created from your camera sensors raw mosaic data which has been converted by your choice into a 8bit compressed jpeg image file format.  If you wanted a higher quality image you could have chosen to convert your sensors RAW data into a 16bit RGB image in any color space you want and save it in a compressed file format that does not use lossy compression. Its your choice how you convert your RAW image file into an RGB image and save it into a imaged format file type. You do no seem to understand what is going on at all.

                        • 9. Re: Dramatic drop in file size - please help?
                          Maddiex Community Member

                          Thank you for taking the time and effort to help me understand my issues. Now let me help you. Not sure if you know this or even intend this but you come across as patronising and irritated with my lack of understanding.  We all have to start somewhere and sometimes we don't even understand the depth of what we don't understand - be nice to us and someday we will understand - perhaps.

                          • 10. Re: Dramatic drop in file size - please help?
                            Maddiex Community Member

                            Hi, this is not a change of PS version problem, it is happening within the same version.  I must have changed a setting (many of which I don't understand ) so unfortunately I can't do your test. Maybe the 16 bit to 8 bit that JJMack suggested is what I did, I will try that.

                            • 11. Re: Dramatic drop in file size - please help?
                              JJMack Community Member

                              My intent what to ruffle you feather and make you think wake up that gray matter between your ears its capable of even more then you know. Think is the key understand what is being done and knowing what can be done. What file formats are all about like Tiff can save layers jpeg only support 8bit color and uses lossy compression and not layers. PNG supports transparency jpeg does not... Populate that gray matter.  Dont take what any bully states on the Internet it doesn't matter at all. Peace.....

                              • 12. Re: Dramatic drop in file size - please help?
                                Maddiex Community Member

                                Thanks JJMack, I have no issues, peace to you too and thanks for your great answers on my other questions.  I do understand the different file formats, I usually convert raw files and save as DNG's for long term orginals and Tiff for layers work, and I do use PNG's occassionally , but I do high volume and hence use jpegs for convenience where quality is not all important (they are generally not going to be enlarged above postcard) and only minor tweaks are required and  I don't need the huge file sizes. I always shoot in raw because while quality is not that important for these high volume jobs it is important that I don't miss a shot due to bad lighting/ flash not firing/me messing up exposure which sometimes can't be fixed as well in PS. 

                                 

                                The problem is my question has still not been answered - there has been a huge change in the size of my jpegs across the board. It is not really important because the resolution is well above what is required for screen viewing and for printing up to A4 size which is all I need, but it bothers me that I don't understand why it has happened. It also bothers me that when I shoot in Raw+Jpeg I am getting a Jpeg at around 10MB but when I convert the Raw file to Jpeg myself it is coming out at 1MB?

                                • 13. Re: Dramatic drop in file size - please help?
                                  Curt Y Community Member

                                  Here are a couple of old thread that may help.  In one it appears that what adjustments you make to the raw image can affect the compression by up to 50%.. http://forums.adobe.com/message/4544650

                                   

                                  The second on makes a good point not to work about megabyte size but pixel size of image. http://forums.adobe.com/message/5661142

                                  • 14. Re: Dramatic drop in file size - please help?
                                    Noel Carboni Community Member

                                    When you save your JPEG you're prompted for a Quality amount, which translates to "how much or little compression" you want.

                                     

                                    How are you setting that value?

                                     

                                    -Noel

                                    • 15. Re: Dramatic drop in file size - please help?
                                      JJMack Community Member

                                      The best reason for shooting RAW is that its very forgiving.  Its like having a peace of exposed film an exposure that does not get destroyed during development.  You can develop it over and over again.

                                       

                                      The truth is there has not been a huge change in image size in your jpeg image unless you interpolated the image size during raw conversion.  If you do not interpolate the image size your RAW data is for  the same number of pixels as you jpeg image with the exception of some outer pixels which are only used to realize inner RGB color pixels in your RGB color image.   In fact there are more bytes required for the RGB image.  For 8bit RGB image have three 8bit values for each pixels. 8bits for red 8 for green and 8 for blue. So each pixel requires 24bits, 3 bytes. Raw pixels have a single 12 or 14bit value for a single color Red or green or blue. For most digital sensors and there are twice as many green pixels as there are red and blue pixels. 

                                       

                                      The quality of each pixels varies with sensor exposure lighting etc.   There is also a quality setting for jpeg from 0 to 12 which influences how compression is performed.  High values in the 10 to 12 range produce  larger files and when the image is encoded into a jpeg file.  When a jpeg file is decoded the image quality is close to the image that was encoded with a high quality value jpeg setting  but its not exactly the same. Some image quality is lost. You will be hard press to see any difference in print quality at quality 10 and 12.  Quality 10 jpeg file are quite a bit smaller then the quality 12 files.

                                       

                                      It is not a good idea to work on an image using jpeg image format with repeated edit sessions. For image quality will drop a little with each edit session.  If you edit in a single edit session you can save the image over and over again in jpeg format without loosing a much image quality it the same as encoding the image once in jpeg.   You loose quality when you use many edit session.  Each session generate a new generation of the jpeg image. Each additional edit session causes a jpeg format decode and a jpeg encode for the save one or hundreds of saves.  The original edit session if done through ACR did not have any jpeg decode. It had a RAW conversion that was later save and encoded in Jpeg format.

                                       

                                      Its the sequence decode encode decode encoed  the cause quality lose each edit session only has a single decode duing open.

                                      • 16. Re: Dramatic drop in file size - please help?
                                        Maddiex Community Member

                                        Many thanks - To JJMAck and Noel - I don't keep the raw files and I seldom edit most of these pictures more than once and I always save at max 12 quality for jpegs. There are hardly ever re-sales on these pictures, they are once off only.  This is for my high volume work only and this is where I have noticed the problem. 

                                         

                                        Of course, I do have many smaller shoots where the quality is very important and I always save these raw files as DNG's, here I will edit the raw file not the jpeg because of the lossy nature of the jpegs, Hence my other question in this forum about how I replace the old jpeg with a new edit to the raw file which you answered very well.

                                         

                                        I don't know anything about the interpolation of the image size, I will need to look into this, and CurtY those threads were very helpful generally to my understanding too, many thanks.

                                        • 17. Re: Dramatic drop in file size - please help?
                                          JJMack Community Member

                                          Whenever you interpolate an image (Change the number of Pixel for the entire image) You wind up with an entirelly new image not a single original pixel remain all pixels were generated by some computer routine they are not ones generated by using lens camera sensor and firmware. Some image quality is lost. 

                                           

                                          You loose more quality when you downsize for your actually throwing away good image details you had.  Which can not be recovered using the generated image.  When you increase the number of pixels the image may print better still the image quality is not as good as the image you started with the added details were generated by a computer not by capturing the actual scene. What you have is an educated guess at details.

                                           

                                          The best pixels you have for you image are the pixels you get from you camera.  If you shoot RAW you do not get a color image from your camera the pixels you get must be post-process into an RGB image to be useful.  If you shoot jpeg the post processing has been done in camera and your stuck with the results.  If you shoot RAW your not.  If you forgot to set the camera white you can use the correct setting during conversion.   While you can adjust jpeg image color that have been  post processes in camera with the wrong white balance setting you can not do it as well as you could when you have the camera RAW data.   You can correct some human error or over sites when you shoot RAW however ever image you want to use must be post processed.

                                          • 18. Re: Dramatic drop in file size - please help?
                                            KR Seals Community Member

                                            You must be using Adobe Camera Raw (ACR) to bring the files into Photoshop. On the main screen of ACR check out the Workflow Options. Its the blue line of text at the bottom of the ACR window. You will see a number of options there for sizing the original RAW CR2 when you open it in PS. In the Image Size section, look to see if the Resize to Fit is checked.

                                             

                                            Perhaps you have very small pixel size set there. Once the Workflow Options are set, they remain the same until you reset them to something else provided you continue and open the image in PS.

                                             

                                            I tested opening a 25 Megapixel image in ACR/PS then saved it for web at 100%. The resulting .jpg was 16 MB.

                                            Ken

                                            • 19. Re: Dramatic drop in file size - please help?
                                              JJMack Community Member

                                              Yes ACR can interpolate image in size either up or down.  I find when I open a 25MB Canon 1d4 CR2 file at its native 16MP size 4896px by 3264px in 16Bit ProPhotoRGB color space and save a 8bit Jpeg at quality 10 the jpeg file size is 5.5MB, when saved at quality 12 the Jpeg file is 12MB.  ACR remembers what setting you used the last time and you can also set work-flow defaults. Double click on the blue line.

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