11 Replies Latest reply on Jan 5, 2015 11:00 AM by trshaner

    Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?

    DSalk

      The subject line says it all.  I have discovered that LR reduces the size of files transferred to Photoshop for further editing when compared to the same RAW file processed in ACR in Photoshop.  For example, a psd file created by LR from a 36 MB RAW file will typically result in a 100 MB psd file.  The same RAW file processed similarly in Photoshop will result in a file around 300 MB.  This makes a huge difference when the files are converted to JPEGs for printing.  The smaller LR psd files result in JPEGs typically under 500 KB where the Photoshop JPEGs are typically around 1.5 MB.   

        • 1. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
          dj_paige Level 9

          MB are not the number of pixels. Do not confuse the two. The megabytes can change and not be a problem. Megabytes is the wrong number to look at.

           

          The number of pixels remains unchanged from the original when you send the photo to another editor. (Unless you cropped the photo in Lightroom, in which case LR will send the cropped number of pixels to the other editor)

           

           

          This makes a huge difference when the files are converted to JPEGs for printing.  The smaller LR psd files result in JPEGs typically under 500 KB where the Photoshop JPEGs are typically around 1.5 MB.

          You should not be comparing megabytes of JPGs, as this is meaningless and will lead you in the wrong direction and lead you to make incorrect decisions. Megabytes does not give you an indication of the quality of the photo. You need to think about pixels and not megabytes or kilobytes.

          • 2. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
            DSalk Level 1

            Thanks for  your reply but I am some what confused by your response.  I understand that the size of a file expressed in KB or MB is not the number of pixels in the file but, as I understand it,  the two are inextricability related, the more pixels the larger the file size.  The more pixels for a given physical size, the more information that is available (e.g., color shades).  I know from experience that, all things being equal (size, resolution, etc.), a print made from a small size (KB) jpg file will not be as good as the a print of the same photo made  from a larger (MB) jpg file.  Maybe there are other factors involved that I am unaware of but this has been my experience and the reason I want to keep the LR converted psd files the same size as those created in Photoshop so I will have the larger jpg files for printing..

             

            As a general question, I would like to know why is there a difference in size between the psd files created in the two programs?  Why does LR create smaller psd files or, conversely, Photoshop larger psd files?  

            • 3. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
              Conrad C Adobe Community Professional & MVP

              DSalk wrote:

               

              The more pixels for a given physical size, the more information that is available (e.g., color shades).

              No, that's not true. Pixels only provide more potential for spatial detail, not color detail. What determines color shades is the bit depth. If an RGB image has 8 bits per channel, it can contain over 16.7 million colors. That's still true if there is only one pixel in the image; it can be any of those 16.7 million colors.

               

              DSalk wrote:

               

              As a general question, I would like to know why is there a difference in size between the psd files created in the two programs?  Why does LR create smaller psd files or, conversely, Photoshop larger psd files?  

              You'll want to look closer at the settings in each program that control how raw files are converted into Photoshop files. In Camera Raw you get those by clicking the blue underlined text at the bottom of the Camera Raw window. In Lightroom they're in the External Editing tab of the Preferences window.

               

              For example, if Lightroom is set to convert a raw file to an 8 bit per channel Photoshop file, but Camera Raw is set to convert a raw file to a 16 bit per channel Photoshop file, the file size of the images coming out of Camera Raw will be roughly twice as large. Or, if Lightroom is sending raw files to Photoshop as TIFF with ZIP compression but Camera Raw is sending raw files to Photoshop in Photoshop format, the Lightroom files will be noticeably smaller, even though they'll be visually identical with no loss of color quality.

              • 4. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                trshaner Adobe Community Professional & MVP

                You need to tell us how you are "transfering" your LR files to PS: Export or 'Edit In' and what settings you are using. If the LR settings you are using are different than your ACR settings then the file size will be different. If they are the same then the PSD file sizes will be the same.

                • 5. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                  dj_paige Level 9

                  Thanks for  your reply but I am some what confused by your response.  I understand that the size of a file expressed in KB or MB is not the number of pixels in the file but, as I understand it,  the two are inextricability related, the more pixels the larger the file size.  The more pixels for a given physical size, the more information that is available (e.g., color shades).  I know from experience that, all things being equal (size, resolution, etc.), a print made from a small size (KB) jpg file will not be as good as the a print of the same photo made  from a larger (MB) jpg file.

                  I agree with Conrad ... all of this is incorrect, and by looking at megabytes or kilobytes rather than pixels will lead you astray.

                  • 6. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                    elie-d Level 4

                    A psd from LR with a 36 MP image will always be 103 MB if it is written in 8 bit depth and 206 MB if it is written in 16 bits per channel. If you are saving out psds from PS that are "around 300 MB", there are a couple possible reasons - you are saving multi-layered psds (psds from LR will always have only a single layer) or you are resampling them in PS and making them more than 36 MP. If the former is the case, flatten the image before saving and it will be exactly the same as the file from LR.

                    • 7. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                      DSalk Level 1

                      Whew!  I didn't think this would turn into such a long discussion!.     OK - my error,  spatial data not color.  But that is loosing focus on my question.  My objective is to get the best print possible from the final JPEG file used for printing..  As previously noted, for a given RAW file w/similar adjustments but with one processed in LR and the other in PS , a print made from the larger of two resulting JPEG files, the larger JPEG file resulting from only  PS ACR processing (i.e., no LR) will result in a better print.  Elie-d appears to have answered my basic question. If LR will always pass a 103 MB file then I assume there is no way to change this size.  In case anyone is interested here is some additional info for consideration.  Both LR & PS using 8 bit mode and 240 ppi..  Procedure in LR: 1) download RAW files from camera CD; 2) make adjustments to photo;  3) using Edit in External Processor, photo transferred to PS in PSD format, 8 bit. 4) file size around 100 MB (103 MB per elie-d).  Procedure in PS:  1) download RAW file to hard drive with Nikon View2; 2) open file in PS - auto opens in ACR; 3) apply essentially the same adjustments (e.g., exposure, highlight, shadow, etc) ) as applied in LR;  4) file opened in PS editor;  5) resulting PSD file size with no further processing (i.e., no layers, etc.) is 310 MB).  The resulting JPEG file created from the LR PSD is typically less than 200 KB whereas the JPEG from the PS PSD will generally be around 1.5 MB.   As an academic question it would still be interesting to know why one gets different size PSD files from LR and PS and what, if any, affect this has on print quality.  As for now I will not use LR to process RAW files.  I prefer the larger PSD & JPEG files I get using just PS            

                      • 8. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                        trshaner Adobe Community Professional & MVP

                        With all due respect–Try listening to the people here who are trying yo help you! File size has little to do with image quality, it's all about pixel resolution and bit depth! Despite being told that you keep posting file size information and nothing about image pixel resolution. I use LR and PS to create PSDs and TIFFs with no quality issues as you report here. I don't doubt you're seeing some anomaly that's affecting your JPEG conversions, but we need more information to help you figure out what's wrong.

                         

                        Try this. Set your Bridge Preferences for Thumbnails as below:

                        Next post a screenshot of the image files in question as below. This will help us to help you.

                         

                        • 9. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                          elie-d Level 4

                          open file in PS - auto opens in ACR; 3) apply essentially the same adjustments (e.g., exposure, highlight, shadow, etc) ) as applied in LR;  4) file opened in PS editor;  5) resulting PSD file size with no further processing (i.e., no layers, etc.) is 310 MB).

                          DSalk, to the best of my knowledge this is impossible. Let me briefly review some digital imaging basics: A color image has three channels, each channel can be written in 8 bit code or 16 bit code or 32 bit code (jpgs are only 8 bit, 32 bit is used for HDR images created by the merging of two or more images). 8 bits is equal to 1 byte and there are 1024 bytes in a kilobyte and 1024 kilobytes in a megabyte; so the equation for an uncompressed image is simple - (number of pixels) x (3 bytes for 8 bit image or 6 bytes for 16 bit) / (1.024) / (1.024). If you are getting a psd that is bigger than 206 MB something is happening in PS of which you are not aware. An uncompressed 8 bit image is visually identical to a 16 bit image because the former can contain 16 million colors and the latter  281 trillion, but the human eye can distinguish only 11 million colors. We need 16 bit images for some kinds of editing that cause loss of colors because 16 bit has plenty to spare but 8 bit not so much, but not for display purposes (e.g. printing).

                          • 10. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                            DSalk Level 1

                            AHAAAA (that's me screaming)!  I'm an officially embarrassed pea brain.  Based on your previous post I decided to conduct a test.  I opened a RAW file in LR, made no adjustments and passed it to PS in PSD format.  You were right on.  The file was 103 MB.   Next I opened the RAW file in PS via ACR w/no adjustments.  As you probably know it was the same size as the PSD created in the LR Edit-in!  I was stumped.  Why did I get larger files on previously processed photos?  Then it dawned on me, while I hadn't added any layers to the photos I had rotated to correct horizon and corrected the vertical distortion in PS!  Obviously this caused the increase in file size.  Sorry for all the confusion on my part.  Thanks to all who replied.          

                            • 11. Re: Is there a way to prevent LR from reducing size (pixels) of files transfered to Photoshop as a psd file for editing?
                              trshaner Adobe Community Professional & MVP

                              DSalk wrote:

                              This makes a huge difference when the files are converted to JPEGs for printing.  The smaller LR psd files result in JPEGs typically under 500 KB where the Photoshop JPEGs are typically around 1.5 MB.   

                              You've only identified why the  adjusted PSD "file size" is bigger, not the JPEGs. As we've pointed out the this change in PSD file size has no impact on the image size or its quality. In order to rotate or change the image perspective the background layer must be placed into layer mode, which increase the PSD file size by ~2x when saved. The image resolution and document size remains unchanged! After performing image rotation and vertical perspective correction on the PSD file the image will have to be cropped to restore straight sides. This reduces the document size (pixel resolution) and JPEG file size compared to the unadjusted PSD file. This assumes both conversion use the same PS JPEG Quality setting.

                               

                              The smaller JPEG file (i.e. 500KB?) is actually being created from the larger PSD file!

                               

                              The only reason it's quality may seem lower is because the image has been cropped and now has a smaller document size (pixel resolution). This has nothing to do with the original PSD file size. Compare the 500KB and 1.5MB JPEG images in Bridge using the thumbnail Preferences settings I suggested. The 500KB image file (from edited PSD) should have a smaller 'Dimensions (in inches)' due to cropping.