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How to reduce file sizes – from RAW to PSD to JPEG

Foto von Luis Quintero von Pexels

Large amounts of data are generated during post-production – previews, composites, layered and non-layered versions, revisions, etc. – also for the client. These files consume storage space and must be backed up. Ultimately, we have to keep an eye on our files and reduce the file size to a minimum – of course, without loss of quality.

Minimize RAW files

Dotphoton Raw (now Rawsie) offers lossless compression of RAW files with up to 80% file size reduction.
Check out their website to get an insight into the list with supported camera manufacturers. There is also the offer of 30 images a day for free, which is fantastic!
If you are a full member of Cherrydeck, you can also get an excellent deal with Dotphoton Raw from them: With the Full Membership, you get 50% off of their subscription.

One important thing to know: the files are converted to DNGs (= Digital Negative Image File; remain readable in Capture One). The DNG format was invented by Adobe to have a pseudo-RAW format. Some people argue that the DNG format is better because it allows for any future software to read it since it is an open standard.
If you carry out this step of conversion retrospectively, changes made in Capture One no longer fit 100%. It is therefore advisable to carry out this step immediately after importing the files – consequently, the first step. The files do not replace the RAW data. You can therefore compare directly where the differences are. Possible changes include lens distortion, image vignettes, skin tone changes, or the absence of .xmp changes.
After performing some tests, however, I conclude that the changes are positive – also apart from the significantly smaller file size.

There is also an option to optimize Lightroom catalog folders from Dotphoton Raw (also included in the free version), which we didn’t test because we use Capture One instead of Lightroom. If you made any experiences here – please feel free to comment in the comment section below.

Minimize PSD/PSB/TIFF files

Sometimes you wonder about the file sizes. Despite minimal, quick processing, the files can reach 20 to 50 times the size. So here are quick tips of our experience to help you out.

In general:

    • Try to work with setting levels and masks. If you create a mask and do little editing there, it will only take up a small space. Complex masks require complex space.
    • Avoids all techniques that make copies of the image (which you should always do for the non-destructive workflow). The same effect occurs when sharpening using a high-pass filter: a complete doubling of the memory requirement. If you use copies of layers, unused areas should be deleted.

Here are several options to minimize your PSD/PSB/TIFF:

    • Try to work with 8-bit if the file does not include many or large gradients (then, of course, use 16bit)
    • Use the Retouching Toolkit‘s actions “Delete identical pixels” and. “Remove help layers” regularly.
    • Try to do local and global Dodge together & local and global Burn together (advanced level)
    • Don’t use frequency separation on skin. And try to use it as less as possible on other surfaces in your file. It will enlarge your file very quickly and heavily.
    • Try to do as many corrections as possible in one adjustment layer instead of several ones (if you don’t need masking and it fits the image). E.g., in selective color,  adjust reds, greens, and yellow tones in one instead of 3 different adjustment layers.
    • Use as few smart-objects as possible: only where they make sense, i.e., if you have to make subsequent corrections or adaptations have to be taken back. Examples are Liquify or the Camera RAW Filter. In case of sharpening or noise, it makes sense to do it without a smart-object on a separate layer/layer duplicate and store the settings in the layer name as a reminder.
    • Use the integrated filter options of Photoshop to find and delete empty layers.
    • Apply masks when the job is approved.
    • Corrections in Capture One need less storage. If the workflow allows it and some corrections can even be better carried out in Capture One, you should choose this way.
    • Export TIFFs via Capture One will delete paths and channels, which reduces your file size. This is useful if your client doesn’t need them anymore.
    • In the beginning, work with PSDs instead of TIFFs for automatic recovery from Adobe in case your Photoshop has a crash. Then, compare how much the same image with layers as TIFF or PSD needs. Depending on the picture, very different results can be achieved here.

Composites – Working with linked Smart-objects:

    • If the same external file is required several times in the document,
    • It often makes sense to edit the elements in the image individually in different documents and to link them together in one document (e.g., compositings – this also makes working in a PSD significantly faster). Here you should make sure that the color profiles are identical.

Minimize JPEG files

We highly recommend buying JPEGmini at a one-time price (no subscription model). We have been using JPEGmini for a long time now and believe that their motto “Reduce file size, not quality” is 100% correct. At the moment, we don’t want to miss their service.
This is a handy tool, especially for discussing revisions with clients – fast upload times & fast download times – or for reducing file sizes to a minimum for Social Media and website exports.

They also have the option of Lightroom, Photoshop, and Capture One Plug-ins.

File structure

Overall, it is recommended to keep the following files at the end of a job:

    • The RAW files used (delete additional ones!)
    • An open file with non-destructive layers (working file): PSD / PSB
    • A final file without or merged layers: TIFF (lossless compression: 16-bit files -> ZIP compression; 8-bit -> ZIP / LZW)
    • JPEG exports of the final result (website, social media, specific customer exports as reference for future jobs)

All files should contain the version number.


Do you have any suggestions, additions, is this post out of date, or have you found any mistakes? Then we look forward to your comment.
You are welcome to share this post. We are very grateful for every recommendation.

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Mareike Keicher

Mareike Keicher, founder of MK Retouching and senior retoucher with several years of experience in postproduction. From an early age, she always has had an eye for details and a talent for drawing. Later, she studied Informationdesign at the Media University of Stuttgart, focusing on digital painting, photography, and design. After her advertising agencies' experience, she really enjoyed the exchange with numerous retouchers & photographers.

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