Understanding Digital Images

If you’ve ever wondered what the difference is between a TIFF and PSD file, what 16-bit means or which color mode is best for printing images, then this is the photography class for you.

Before looking at the Photoshop interface and main features and controls, it’s important to understand each of these concepts and how they affect your images. Understanding all of this may seem overwhelming at first, but in this photography class Karl explains each concept clearly.

Here he provides detailed explanations of different file types, resolution, bit depth, color profiles and color modes, outlining all you need to know about digital images.

In this photography class we cover the following:

  • Image file formats: Types of digital files

JPEG | TIFF | RAW |  PSD | PSB

  • Pixels & resolution
  • Bit depth
  • Colour space & colour profiles
  • The difference between RGB and CMYK
  • Recommended colour modes for printed images
  • Resizing images

If you have any questions about this course please post in the comments section below ?

Comments

  1. simiruffi

    Hi Karl,
    Which Camera Settings Should You Use?
    I have the following options:
    – RAW 12 bits or RAW 14 bits?
    – sRGB or Adobe RGB? (I suppose Adobe RGB ;-))

    Additional Questions:
    Why should I convert an image to 16 bits in Photoshop when my file only has 14 bits?
    How does Photoshop handle the missing 2 bits?
    Un grand merci pour vos réponses! 😀

    1. Hi, if you have RAW 14 then use it and choose Adobe RGB. You should convert an image to 16bit from 14bit because then any following retouching or colour/contrast work has a greater level of tonal range to work with and to avoid banding/blending problems. Photoshop will build the new 2 bits but that’s not quite how it sounds, there are some videos in the end of this section to do with Bit Depth and Colour Space that will help you: https://visualeducation.com/section/photoshop-tools-and-techniques/

  2. CambsCreative

    Karl, I’ve often seen you “Neutralise” the colours in an image in Phocus by clicking on a feature and then clicking on a certain area of the subject. What exactly is this? Is it just ‘White Balancing”? Can you tell me what it is you are clicking on etc so I can figure out how to do this in Capture One.

  3. Hi Karl, many thanks for your insight! In order to get the best quality, can I shoot in TIF format instead of RAW? Or is it best to always shoot in RAW and then convert to TIF? (If RAW is the best way to go, what software should I use to convert RAW files to TIF files?) Thank you so much!

    1. Hi Nic, always shoot in RAW and then convert to either Tif or PSD in 16bit. You can use various software for handling the RAW files depending on whether you want to shoot tethered or not and which camera you are using. For example a good tethering/RAW software is Capture One but you can also use Lightroom to shoot tethered and handle RAW. Photoshop can also handle most RAW files and you process them in Photoshop Camera Raw and then can export them as 16bit PSDs to continue working on them in PS. You can (if necessary) convert them to a smart object and leave them as RAW files while you work on them in PS (we have a class on that somewhere) but I find this a bit unnecessary.

    2. First props to how you explain things…i am learning a ton. One thing i need clarifying on is when i first put a raw file in PS…do i go ahead and put it in PSD..and 16 bit for editing, then begin my editing? Thank you

      1. Hi, yes once you have made your adjustments to your raw file then export the RAW file as a PSD or Tiff in 16bit and then open in PS.

  5. Hi Karl,

    What should the width and height of a picture be for screen and printing or does it depend on how you cropped it?

    2. Hi Maryke, it depends on the size of the screen print you are having made. For the very biggest prints for your wall then of course you want to provide the printer with the full resolution file or even consider increasing the resolution of the image by using Topaz Gigapixel or Photoshop’s Super Resolution feature, this is only necessary with exceptionally large prints (a few meters across) but can help with moderate size prints too.

  6. Hi Karl,

    I’m used to working with raw files in Lightroom, but am now keen in getting started with Photoshop. Just get into terms on how that will affect my workflow, what is the main advantage on working with tiff vs raw in photoshop?

    Thanks!

    1. Hi Paulo, you can actually work with RAW files with Camera RAW in PS too. And it is also possible to continue to work with the file as a ‘Smart Object’ which basically means the layer will link back to the RAW file if you need to update something. However this process (we have a class on it) is somewhat convoluted and once you done you main RAW adjustments in Camera RAW or LR it’s usually easier to convert it to a PSD or Tiff in 16bit and then you have almost as much information as a RAW file anyway but with an easier way to control lots of layers and speed up the workflow. I’d suggest you follow the process in my course first and then when you’re familiar with Photoshop then look into ‘Smart Objects’.

  7. Hi Karl, I have always wondered why all my photos look different in terms of color in different devices. It’s like after I edit a specific photo on my laptop and I send it to someone else and if they are seeing that same photo on an iphone then the colors seem more raw/less bright. The colors aren’t bright at all when compared with the same image on a samsung phone. Right now I just checked by uploading a photo in photoshop and the default color profile setting is on sRGB IEC61996-2.1. Could it be possible that the reason for which different devices show different color be due to that fact that I haven’t set my color profile to Adobe RGB(1998)?. To be honest I never really knew about the color profiles up until this moment. Thanks a lot for your tutorials. It’s really helping me a lot to progress my knowledge in photography as well as in post production.

    1. Hi Niks, that will be part of the reason but the most common reason is simply that all devices/screens yield different results, viewing conditions, ambient brightness, time of day, type of screen etc. The best we can ever do is use proper calibrated screens and good colour management procedures and then hope that everyone else’s screens aren’t too far from the industry benchmark. I spend a huge amount of time using all the correct procedures and then shiver sometimes when I see someone viewing my website on a phone with the brightness on zero!

  8. Hi Karl! I have a MacBook Pro. What’s the proper Color Calibration for my screen? how would I know what’s good and what’s not?

    1. Hi Malex, there can unfortunately never be a proper calibration on that type of screen simply because they are not capable of producing all of the colours accurately because of the type of display technology they use. That being said they are still very good for laptop screens and if you use a calibrator such as an Xrite then you will benefit but for absolute colour critical work you would need to consider buying a second screen that you can plug into your macbook which can be properly calibrated.

  9. Charliestephens

    Hi Karl, I am enjoying very much all your tutorials! I decided to shoot in sRGB as I like to print my work ( canon pixma pro 100)I use colour correction in camera via colour rite pass port and calibrate my laptop ( MacBook Pro ) and desk top ( iMac mini plus “generic TV monitor “) using “ colormonkie” , I usually create my own icc profiles for the papers I use but find the downloadable icc profiles more than acceptable. The reason I shoot in sRGB is that in every monitor that I have used and tested all achieve 97% sRGB gamut and less than 80 % AdobeRGB . My rational is I want to see the colours in my prints as I see on screen. Is my logic sound?

  10. Hi Karl,
    Thank you for this information. I feel I understand digital files a lot better now. However, I wonder, if larger bit depths are yield a greater range of colors, why should one choose to edit in 16-bit instead of 32-bit? Thanks.

    1. Hi Ariel, because if you choose 32bit you will have to borrow a computer from NASA to process the images. That and it is currently beyond what’s necessary based on the display options our visual perception and computer power. There are some situations in 3D software where have 32bit available is useful to increase dynamic range when applying images maps and reflections to objects etc.

  11. Karl, for years now I haven’t understood RGB. I was taught at school that the three primary colours are red, YELLOW and blue and those three colours cant be made by mixing any other colours. How can it be that the adobe colours are red, GREEN and blue? Green is made by mixing blue and yellow so how come the three colours don’t include yellow?

    1. Hi, the key difference is you’ve not been taught the ‘additive colour model’ which relates to light and the frequencies of light, in fact this really should be the only colour model in my opinion. The other colour model exists because it regards mixing pigments like ink and paint and because of impurities in the pigments it works differently to mix colour. You’ll find this useful https://en.wikipedia.org/wiki/RGB_color_model

  12. Hi again, Karl. Thanks for your prompt and informative reply; I now have a much better understanding what’s going on when I print my photos. My concern was the opposite of “wasting” ink by using “too much”. It had occurred to me that using a lower DPI might put insufficient ink on the page, which in turn might result in a poorer quality and less durable print. But thank you for your concern about my bank balance! LOL

  13. Hi Karl,

    This may be a stupid question, but does printing with a higher number of dots per inch put more ink on the page?

    1. Hi Graham, 300dpi is the standard requirement for the digital image file settings. The reality is that the printer (inkjet) is laying down about 1200dpi any way, although the process of laying the dots is not quite the same as the pixels in the image and therefore resulting in a smoother tone. I don’t think you need to worry about the ink. Ink is expensive i admit so print small test strips first before you commit to your final image.

  15. Hi Karl, i have an image and i opened its image properties there it says

    Horizontal resolution 300 dpi
    Vertical resolution 300 dpi

    I imported same image in Photoshop and exported (jpg) without any editing and now, in properties it shows

    Horizontal resolution 96 dpi
    Vertical resolution 96 dpi and sometime its 72 ppi.

    In photoshop i checked image size, there it is 300 dpi.

    Can i take output image same as the original image resolution (300 ppi)

    what is difference between dpi & ppi.

    Thanks.

    1. Hi Srinivasan, there is something wrong here? Anyway DPI is dots per inch and PPI is pixels per inch so they are basically the same thing. However your image has been changed from 300 dots to 96 dots but what you really need to check is what the total image size is: how many pixels wide by how many pixels tall that’s what’s important. The dots per inch can always be changed after.

  16. Hi Karl, at last I understand pixels and resolution, the difference and most importantly, how to use them for different purposes. You explain them so well. Thanks a mil…!!!

  17. Hi Karl, to what color space would you suggest setting the camera to, sRGB or Adobe RGB? What is the difference?

    1. Hi Giovanni, I’d go with Adobe RGB as it is a large color space and then continue to work on the image in Photoshop in Adobe RGB and then convert to SRGB if you are sending the image to the web or digital media/video etc. For print with good labs you can leave the image in Adobe RGB and let the labs RIP convert the image. If you are shooting for magazine then the final conversion will be to CMYK and this is better from Adobe RGB too.

  18. in this video, you explained how CMYK is simply there so you can look at what the printed result will be. You mentioned that you shoot in RGB and edit in RGB and sent it to the print lab and the lab will convert the image from RGB to CMYK……my question is (please keep in mind yesterday was the 1st day I have ever even OPENED photoshop!)… Does converting from RGB to CMYK, have a significant visual difference? I guess I’m wondering if after I edit, and before I print, if I should convert to CMYK myself to see any differences? I hope that question made sense (it did in my head, but not sure how to convey what I’m thinking) 🙂 thanks!!!

    1. Hi Ashley, yes converting from RGB to CMYK in photoshop will result in noticeable differences but these are usually only perceptual in relation to lithographic printing on printing presses and the simulations in photoshop are designed for that purpose to simulate for designers what will happen in say a brochure. However in photographic lab inkjet or RA4 process printing things are somewhat different as the type of inks used are much more vibrant and often instead of a 4 ink process they use a 6 and sometimes 9 ink process, resulting in images far more vivid than those of a litho process. It is also worth mentioning that the choice of paper from a photolab has a large influence on the final appearance, contrast and vibrance. My suggestion is not to convert to CMYK, use a calibrated high quality monitor and find a professional lab that you can trust and run tests on various stocks of paper to establish what suits best the type of work you hope to produce. All the best Karl.

  19. Hi, Karl,

    What are your thoughts of using AI/neural network upscaling where there’s not enough image data to hit the resolution mark or for extra sharpness? These sorts of upscalers don’t just use bicubic upsampling or sharpening like Photoshop would, but actually analyze the image data and retain sharp details and lines upon upscale – basically a much better job than Photoshop could do. I always turn to them for lower-res assets at work.
    I was wondering if you ever used anything like this and what your thoughts are, if any.

    1. Hi Rimantas, I’d only read an article about this I think on the BBC technology page a few weeks ago and whilst the results were impressive they were still plenty of artefacts and problems with the upscaled images. Also the examples shown were of images taken from very very low resolution so it would be interesting to see what it could do with say a regular 12 or 18mp image. I’ll be honest with you though it doesn’t appear that this solution will oust the capabilities of say a 100mp Hasselblad as the data is not there then it’s just a computer/AI making a guess, which is never as good as having all the facts in the first place.

      1. Thanks for the reply, Karl. I was wondering that because not all of us have access to 100+ Mpix Hassies and maybe a 30Mpix image could be upscaled to push it juuust a hair towards an acceprable print in certain scenarios.
        While there definitely are artifacts typical with upscaling, I’ve at least come to rely on such upscalers to keep the lines sharp, something PS does not yet do well, even with the latest upscaler of theirs. Though I’m sure you won’t need anything like that with your files! 🙂

  20. Hi Karl,
    This bits of information has really helped me to have an extensive knowledge on my images.
    One of the challenges I had with my images was that,prior to this tutorial, I discovered that I usually have a lots of changes in colour spacing which usually affect my images ezpecially when clients view my images through their phones.
    After I followed this wonderful tutorial, I discovered I have not been applying any of the information I got from this tutorial.
    Many Thanks
    Oluwatobiloba Amusan
    Nigeria

  21. Hi Karl I have most of your DVD’s too you have made an photographer out of me tho the years. Justr an Question as I have moved to light room as photoshop bridge is not to good. well that what I think lol. I use lightroom but do I loss info from moreing from lightroom to photoshop then move back to light room. or is there and eazy way.

    2ed Question is is there a way to do 3D gray scale relief for carving with photoshop its for a friend to see if we can and how we find more info on.

  22. Hi Karl
    Just to say I think these tutorials are brilliant. I have been on various workshops over the years and have mostly switched off after a few minutes of techi stuff! But for me this is at the right pace and it’s sinking in! Well don’t test me on it!
    So well done.
    I have most of your dvd’s which I purchased several years ago and they were brilliant, but now having access to them on your tutorial site is so valuable to

  23. Like to know how we can convert on 16 bit files if we have 8-bit raw files using Photoshop/Lightroom. Is there such option available in PS/LR and whats the drawback if we do so? Will there be any degradation of quality when we convert 8-bit file to 16-bit file in Photoshop/LR while we edit? If we are doing composite using the mix of 8 bit and 16-bit files, will there be a seamless merging of end result or we see some differential artifacts in the end result.

    1. Hi Melvin, my first question is why aren’t you able to generate 16bit files out of the raw software in the first place? My normal process is to grade the RAW file in Phocus or LR and then export the RAW file as a 16bit tiff and then I start any necessary photoshop work. If you only have 8bit images then you will still be better to convert them to 16bit before you start photoshop work.

      1. Hi Karl, I get the same, I shoot with a Canon 70D and my raw file is only 8 bit, is that something to do with the camera that we are shooting with? is there a setting that we can change on the camera? How important is to get to 16 bit instead of 8, is the quality of the image really compromised?. Thanks
        Very happy I joined the course btw, it’s great!

        1. Hi Leonor, you would have to check in your camera menu settings, it might be able to achieve 12bit but that would be in the settings. If it only shoots in 8bit convert the image to 16bit when you export the digital file and before you do any post production/retouching work, it will help you with hight quality during the post production stage.

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