5 Replies Latest reply on Jan 5, 2018 7:52 AM by Abambo

    Digital images from Great Photographers posted to Muse

    johnw85606503

      Hello,

      I am a seasoned Publisher and Editor. I have been working with Photoshop since 1988. I have a new digital project. It is #13 of my Publishing career. I am having trouble with finding the best possible image reproduction for my project.

      1. I use 72 DPI - can I move it to 96 and will it make a difference?

      2. Why are some images better than others on the Internet? What are the specs to get there?

      3. Is this method of asking correct?

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        • 1. Re: Digital images from Great Photographers posted to Muse
          D Fosse Adobe Community Professional & MVP

          Pixels per inch (ppi; sometimes erroneously referred to as dpi) is a print parameter. It does not apply on screen.

           

          On screen, the image pixels align to the screen pixel grid and that determines the effective ppi on screen. This pixel grid does not exist on a piece of paper, so a pixel grid has to be invented. That's what the ppi setting is.

           

          Most images need to be resized for screen. This tends to soften and blur the image. For this reason it's essential to run a new round of sharpening after this resizing. Done carefully, this can make a huge difference, and make the image really "pop". It's also important that the site doesn't automatically scale to browser width (responsive design). While web designers love this, it ruins image crispness.

           

          IOW, an image should be prepared for a final screen size in pixels. Screen resolution used to be 1600-1900 pixels wide overall, so it was easy to settle on around 1000-1200 pixels image width. Now, however, the new generation of high density displays has changed those rules. Most browsers solve that by simple pixel-doubling when they detect such a display, so 1000-1200 pixels will still work. But you don't get the potential advantage of the high screen resolution.

           

          It's also possible to upload two versions of the image, one for traditional displays and one for 4K displays. The browser then chooses one according to detected screen resolution. I don't know the technical details about this (but they probably do in the Muse forum).

           

          Also remember to convert to sRGB and embed the profile, to preserve colors as intended.

           

          Other than that, a great shot tends to survive a lot of beating

          • 2. Re: Digital images from Great Photographers posted to Muse
            Abambo Adobe Community Professional

            johnw85606503  wrote

             

            Hello,

            I am a seasoned Publisher and Editor. I have been working with Photoshop since 1988. I have a new digital project. It is #13 of my Publishing career. I am having trouble with finding the best possible image reproduction for my project.

            1. I use 72 DPI - can I move it to 96 and will it make a difference?

            There will be no difference as the screen considers pixels and not dpi in relation to the size in mm or inch. For screen resolutions 72dpi was introduced by Apple with their very first Mac computers. It has no incidence on image quality. 96 dpi is what Microsoft introduced as screen resolution. Both were intended to give a clue on the display size of a picture on the screen. Today and with high density displays, this is no more useful. Anyhow, it was never used for something of use even in the past and only confused the people.

            2. Why are some images better than others on the Internet? What are the specs to get there?

            Also historically it was useful to size the picture in pixel to the size it was displayed. So a picture displayed in 200x300pixels was 200x300pixels. This had the advantage that the picture was displayed at the best possible quality and it's size was not higher then needed. Today, web designers have a multitude of displays and display sizes to consider, so they need to make a compromise. The browser will size to display size. As for the profile, older browsers do not consider colour profiles and simply assume sRGB. If, however the colour is coded differently (say AdobeRGB), colours will be bad (dull in case of AdobeRGB). So I agree with D Fosse to convert to sRGB, but there is no need to embed the profile for sRGB (takes up some space, but also today, this is not any more the most relevant factor).

             

            The Photoshop "Export As" functionality gives you a lot of possibilities to optimize the image quality vs size.

            If you (pre)view your image at 100% you see directly the impact on the quality, when playing with parameters. The Quality parameter for JPEG files compromises size vs image quality, the resample parameter effects the final sharpness impression of the picture, metadata allows for adding or retrieving some data, colour space allows for sRGB conversion (you see, there is no other choice...) and/or embed the profile. For sRGB I never embed the profile.

            3. Is this method of asking correct?

            Yes.

            • 3. Re: Digital images from Great Photographers posted to Muse
              Mylenium Most Valuable Participant

              1. I use 72 DPI - can I move it to 96 and will it make a difference?

              Nope. The web runs on absolute pixels. Browsers are DPI-aware of course, but it's not relevant for the web pages themselves, only for how pages are rendered on-screen. Specifications for dealing with high-res imagery have been considered for years, but it's a low priority and there is no standard for it.

               

              2. Why are some images better than others on the Internet? What are the specs to get there?

              Same old, same old... Color management vs. image content vs. JPEG compression vs. the rest of the world not caring about this stuff. A lot of times it's also complicated by service providers re-compressing, scaling and cropping images to suit their standardized templates, save bandwidth and storage on their servers and so on. Discussing this alone could fill an entire book. basicalyl you never know how an image is going to look until you actually uploaded it. The only way to have full control would be running your own server and even then the limiting factor might be that people get to see different versions of your images e.g. when coming in through a web search and hitting Google's cached versions or a condensed AMP page on a mobile device. not meaning to discourage you, but it's more or less a game you can only lose, so life is easier if you don't over-obsess on it. You could doctor up your image perfectly in your studio and it might still end up looking rubbish on the web. just follow the generic procedures already laid out by the others and keep your fingers crossed...

               

              Mylenium

              • 4. Re: Digital images from Great Photographers posted to Muse
                D Fosse Adobe Community Professional & MVP

                Abambo  wrote

                 

                convert to sRGB, but there is no need to embed the profile for sRGB

                 

                Today all browsers color manage correctly as long as there is an embedded profile (excluding IE/Edge, which botch it for other reasons).

                 

                An untagged file viewed on a standard gamut screen is not the same thing as an sRGB file with color management.

                 

                Every owner of a wide gamut display should know this of course - but few people realize that this applies to every monitor in existence. No monitor matches sRGB completely, wide gamut ones just match less. LCD displays have a marked shadow dip that the profile corrects, and the primaries aren't where they're supposed to be. This affects something as obvious as sky blues, for instance. Without color management, they tend to be too cyanish or too magentaish. This matters!

                 

                Firefox at default mode 2 does not color manage untagged material. You have to manually set it to mode 1 for this. Chrome only very recently adopted this policy of assigning sRGB to untagged material.

                 

                So yes, there is every reason to embed the profile. It's insurance. And the only cost is a mere 3kB extra file size, hardly worth considering today. I'd say there is no reason to not embed the profile.

                • 5. Re: Digital images from Great Photographers posted to Muse
                  Abambo Adobe Community Professional

                  https://forums.adobe.com/people/D+Fosse  wrote

                  So yes, there is every reason to embed the profile. It's insurance. And the only cost is a mere 3kB extra file size, hardly worth considering today. I'd say there is no reason to not embed the profile.

                  May be that I'm still to conservative with trying to squeeze every bit out of my image files. However, My understanding until now was that for internet purposes untagged files should be interpreted as sRGB, an all of my browsers on my Windows 7 system do so up to now.