Digital Imaging

Photoshop: What is a Master File, and why do I need one?



From Matthew S in San Diego, CA:  

“Once you capture an image in RAW (or a 16-bit scan), what is the best way to save the image for printing purposes? Or should I convert the image to another format? I typically convert everything to a max
quality JPG.  Supposedly any “lossy” degradation will be unnoticed to the eye, or so I’ve been told. But, is this the best way? I’d love to have this clarified.”  




Before I can fully answer your question, Matt, you might want to review this post on my blog –  mostly a wee bit technical, but well worth the time:


Why shoot in 16-bit (RAW), rather than 8 bit (JPG)?


Once you read through it, you’ll see why saving your important final images in JPG is not such a good idea, particularly from a technical standpoint …


So, what to do?  Let me introduce you instead to the concept of a Master File – the best way to prep your important images for a multitude of uses, including printing.


If a picture is truly worth a thousand words, then the chart  above is an overall “visual” representation of a proper Photoshop workflow for your important images – notice that everything is centered around the Master File (as an aside, you can download a free step-by-step “linear” workflow here).


Creating a Master File is NOT for every image: it’s for those images that you want to spend time with, doing all that’s necessary to make your image “pretty”.


Here’s where you pour your artistic “blood, sweat and tears” into your image (for awesome results, try using the methods shown in my  book,  “Not Just Another Photoshop Book”, available exclusively on Amazon (Kindle, too!) …


What is a “Master File”? It’s a 16-Bit, un-flattened, un-sharpened, un-cropped, un-resized file, designated as such in its file name, and saved as a TIFF or PSD.


Why create a Master File?


•  It’s Multi-purpose: Use it to create separate files for a specific print size or printer, for the Web, for magazine output, etc. and you’ll stay consistent between those files.


•  It’s easily correctable: for color, contrast, cropping, enhancements, etc. non-destructively (loss of digital information).


•  Sharpening is applied according to your print size: Let’s say that your Master File is created from a RAW file – It might be around 13″x20” at 300 ppi – If you sharpen for this size and reduce the file to prep for a 4×6 print, it will be over-sharpened.


So, bottom line, Matt: I’d strongly suggest you NOT save your final important images as a JPG, and consider the concept of a Master File for your important images, saved instead as a TIFF or PSD – and thanks for the great question!




John 🙂


PS – By the way: if you want a genuine, bonafide, certified “pro” (me!) to create a Master File for your best images (AND make it a “teachable moment”), that is a service I provide – more here:



Why shoot in 16 bit (RAW), rather than 8 bit (JPG)?



I’ve been asked this question so much lately that I had to share – In this post, we’ve got two important questions (and two timely answers) as seen from a “post-processing” point-of-view



Question #1:  


From Kris K in Gilroy, CA: 


 “You’ve mentioned shooting in 16 bit RAW files, and I’ve always used 8 bit JPG’s.  What would be the advantages and disadvantages of using 16 bit versus 8 bit for a landscape architectural photographer?”  




Before I can fully answer your question, Kris, allow me to put on my “propeller-head” hat for a bit, so if “technical” is not your thing, don’t tune out, as this is good stuff…


Let me introduce you to the concept of Tonal Compression. This is the inevitable reduction and degradation of the original scene from your eyes to the print. It’s pure physics – the range of colors reproduced shrinks throughout the process.    


Let’s say, for example, that our eyes see 100 shades of red.   The camera, shot in RAW (16 bit), may see only 70 shades. Then Photoshop may only see 50 shades of red, and the printer may only print 40 shades of the original 100 shades available.


If, however, you shoot in JPG (8 bit), tonal compression will limit you to only 10 or 15 printable shades of red – not good!


So, how can you minimize some of the effects of tonal compression?  Three things:     


1)  Shoot in RAW (or scan in 16 bit) – discussed below …


2)  Use a proper Color Working Space in Photoshop – I strongly recommend “Adobe RGB 1998” or “ProPhoto RGB”.


3)  Have your Color Management “house” in order (discussed in my free Color Management PDF, “The 3 Steps to Successful Color Management”Download here…)


So, to answer your questions:


The advantage of shooting in 16 bit?  Simple – – more information equals better final output.  There’s power in a 16-bit workflow – it’s not just “double” the amount of information; it’s a hundred-fold increase.


Here’s where you’ll see problems in an image shot in 8 bit: Because of the effects of Tonal Compression, poor results will show up first in “gradients”, or “continuous-tone” areas where the tonal qualities change subtly – a perfect example is the sky.  Kris, since you’re shooting landscape and architecture images, the sky is a critical element, and it’s rarely the same shade or brightness of “blue” throughout your image.


A more specific example: Most sunset images shot in 8 bit have “banding”, posterization, and digital noise – they just look fake as the “gradient” changes, due to the effects of Tonal Compression.  That same sunset, shot in 16 bit, won’t have near as many problems with it.  In addition,  if you need to punch up the sky by increasing the “blue” saturation, chances are that you can do so in 16 bit without major problems – it just won’t happen effectively in 8 bit. 


The disadvantages?: In my mind, only two, neither one of them a “deal-buster” when deciding whether to shoot in RAW / 16 bit: Time and Memory – It takes a bit more time (and education) to work on your image in the Adobe Camera RAW plug-in, and a bit more space for file storage on your computer (but memory is really cheap right now)


Do I shoot in RAW / 16 bit for everything? Of course not; as much as I love my grandkids, I don’t shoot RAW when photographing them, as the “audience” for the final output are relatives and friends, who just want “snapshots”.  But for those images that are more than snapshots, I’ll shoot RAW every time.




Question #2:


 From Bill S. in Seattle, WA:  


“I’m a rank amateur photographer and new to Photoshop.  I belong to a camera club, and all of my photographer buddies tell me to shoot RAW for my important work, rather than JPG’s – – Why?”   




Your photographer buddies are right – You should be shooting in Camera RAW for your important work — the results are worth it!


A RAW file is different from a JPEG in 2 major respects:


1) There’s much more information in RAW (16 bit vs. JPG’s 8 bit)


2) There’s automatic “file compression & processing” built into the creation of a JPG, whether you want it or not.  The camera’s computer chip, essentially, is telling you what it thinks your image should look like.


In addition, JPG has other limitations:


•  Every time that you open, work on, and save a JPG, there is degradation because the JPG compression scheme is not “lossless” – it dumps pixels, whether you want it to or not.


•  You cannot save a JPG in 16 Bit


•  You cannot save a JPG with Layers (critical in Photoshop)


But it really all boils down to “digital information” – the more you’re able to capture when you shoot, the more information you have to effectively create your image.


•  (JPG) 8 Bit: 255 values of each RGB color (255³)  = 17.7 Million combinations of RGB values


•  (RAW) 16 Bit: 65,000+ values of each RGB color (65,000³) = 281 Trillion combinations of RGB values  – a hundred-fold increase over 8 bit!


Why do you need all of this information? You’ll have a better chance of reproducing your original scene more accurately, because you’re capturing a greater range of colors and luminance.


RAW does have one “limitation”: You can’t open a RAW file directly in Photoshop. You must first work with it in the Adobe Camera RAW Plug-in (ACR) before “sending” it to Photoshop.  By the way, ACR is a separate program, but included with (and “linked to”) Photoshop.


You can learn more about working with RAW files in my Photoshop book, “Not Just Another Photoshop Book”, which is available exclusively on Amazon, in either Paperback or Kindle format:


Also, if your Camera has the option of shooting “RAW” + JPG”, then you should do so – It takes up little in memory, and gives you a quick “look-see” image that’s been “processed” for contrast, color, etc (albeit by a computer chip!). Oh, and I frequently hear folks say “My JPG looks better!” – – once you learn how to properly work on a RAW file, you’ll never believe that again!


Questions?  Comments?  I’d love to hear from you …


Thx again, and cheers,


John Watts 🙂




September 2019
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