Trouble with print resolution

[thomaso]

On 5/28/2021 at 6:57 AM, LeaS said:

Are you saying that if we see it blurry at 100% then thats how it will look in a print?

 Nearly. Screen and print differ in their resolution. Consider that your monitor image is built with hardware pixels. 1 monitor pixel is the maximum detail you can see, smaller details can get visible on screen only if you zoom in (and make this way a tiny detail getting displayed with more than 1 monitor pixel). The monitor resolution isn't only what you define/set to be used by the graphic card (which is variable) but is also related to the physical hardware size of the monitor pixels (which can't be changed). Years ago it used to be about 72 px per inch, meanwhile monitors can have up to ~400 px per inch, means their hardware pixels became smaller. Compare the impression of sharpness on a modern smart phone screen which is meant for a distance of ~20cm (like reading a book) with a 27 inch desktop monitor which is used at a distance of ~ 50-100 cm. That's why hardware pixels on phone screens must be smaller whereas on large monitors may be larger.

Our preferred viewing distance is related to the viewing angle of the human eyes. In photography the term "normal" lens comes from our natural viewing angle. Consider that we can't zoom with our eyes, we only can move their focus, so the eye's angle is always the same. Since it is an angle, closer objects may and must be smaller and increase with increasing distance. Though it is even different concerning details (~resolution / see below: text vs. shape vs. color) there is this "normal" angle around 45º which feels comfortable when we look at wall pictures. But because the eyes can't zoom their resolution decreases with increasing viewing distance.

… …

So to see exactly the same amount of details on your monitor like in a print you must set its zoom factor so that the physical resolution is the same as the print resolution. But since your monitor usually doesn't have the print resolution of 300 dpi the screen image will take a different (larger) size to display the same amount of details – whereas the same resolution (higher pixel density) would require a smaller size. That's why I started the answer with "Nearly".

I agree your 100% screenshot looks blurry. As others mentioned before you did not tell yet the original size (pixel dimensions) of the image file as shot by the camera. Upscaling the image, e.g. to achieve 300 dpi for 1 meter image width, will cause a loss in sharpness, because during upscaling every single image pixel gets increased. For instance: if the camera delivers 5000 px width then upscaling to 10000 px will enlarge each image pixel by factor 2.

5 hours ago, LeaS said:

So in saying this, Any tips on photographing artwork?

A.) "divide" the object (the painting) into 4 photos + combine them on the computer to 1 larger photo. Means pict 1 takes the upper left quarter of the painting, pict 2 the upper right etc. Therefore it's useful to avoid any distortion in each photo, e.g. caused by a.) a wide angle lens or b.) a not-straight (rectangular) viewing angle. Don't rotate the camera on the tripod but move either the painting or the tripod parallel to each other. This technique is also used by "gigapixel photography" (because it results in photos with a large number of pixels)

B.) Use a specialized software to upscale the photos. The market is developing continuously, in my experience TopazLabs "Gigapixel AI" is quite good (note: it needs your time to achieve optimized results because it offers various detailed settings, depending on the input details).

But first I'd recommend you to upload a sample photo of your camera in its original file format (.raw, .nef ?). That might result in feedback of the community which possibly give more hints for your current equipment and situation. One of the most important technical part for sharp images in high resolution is the lens quality. It might even be a useful, valuable option to rent a high quality lens just for the days you photograph the paintings. Depending on your current lens the difference can be impressive and might reduce the need for further editing. The lenstip site offers a range of lens reviews, including detailed info about a.) max. resolution and b.) 'optimal' aperture ("critical aperture", which is neither the smallest nor the largest one).

[LeaS]

On 5/30/2021 at 11:42 AM, thomaso said:

 Nearly. Screen and print differ in their resolution. Consider that your monitor image is built with hardware pixels. 1 monitor pixel is the maximum detail you can see, smaller details can get visible on screen only if you zoom in (and make this way a tiny detail getting displayed with more than 1 monitor pixel). The monitor resolution isn't only what you define/set to be used by the graphic card (which is variable) but is also related to the physical hardware size of the monitor pixels (which can't be changed). Years ago it used to be about 72 px per inch, meanwhile monitors can have up to ~400 px per inch, means their hardware pixels became smaller. Compare the impression of sharpness on a modern smart phone screen which is meant for a distance of ~20cm (like reading a book) with a 27 inch desktop monitor which is used at a distance of ~ 50-100 cm. That's why hardware pixels on phone screens must be smaller whereas on large monitors may be larger.

Our preferred viewing distance is related to the viewing angle of the human eyes. In photography the term "normal" lens comes from our natural viewing angle. Consider that we can't zoom with our eyes, we only can move their focus, so the eye's angle is always the same. Since it is an angle, closer objects may and must be smaller and increase with increasing distance. Though it is even different concerning details (~resolution / see below: text vs. shape vs. color) there is this "normal" angle around 45º which feels comfortable when we look at wall pictures. But because the eyes can't zoom their resolution decreases with increasing viewing distance.

… …

So to see exactly the same amount of details on your monitor like in a print you must set its zoom factor so that the physical resolution is the same as the print resolution. But since your monitor usually doesn't have the print resolution of 300 dpi the screen image will take a different (larger) size to display the same amount of details – whereas the same resolution (higher pixel density) would require a smaller size. That's why I started the answer with "Nearly".

I agree your 100% screenshot looks blurry. As others mentioned before you did not tell yet the original size (pixel dimensions) of the image file as shot by the camera. Upscaling the image, e.g. to achieve 300 dpi for 1 meter image width, will cause a loss in sharpness, because during upscaling every single image pixel gets increased. For instance: if the camera delivers 5000 px width then upscaling to 10000 px will enlarge each image pixel by factor 2.

A.) "divide" the object (the painting) into 4 photos + combine them on the computer to 1 larger photo. Means pict 1 takes the upper left quarter of the painting, pict 2 the upper right etc. Therefore it's useful to avoid any distortion in each photo, e.g. caused by a.) a wide angle lens or b.) a not-straight (rectangular) viewing angle. Don't rotate the camera on the tripod but move either the painting or the tripod parallel to each other. This technique is also used by "gigapixel photography" (because it results in photos with a large number of pixels)

B.) Use a specialized software to upscale the photos. The market is developing continuously, in my experience TopazLabs "Gigapixel AI" is quite good (note: it needs your time to achieve optimized results because it offers various detailed settings, depending on the input details).

But first I'd recommend you to upload a sample photo of your camera in its original file format (.raw, .nef ?). That might result in feedback of the community which possibly give more hints for your current equipment and situation. One of the most important technical part for sharp images in high resolution is the lens quality. It might even be a useful, valuable option to rent a high quality lens just for the days you photograph the paintings. Depending on your current lens the difference can be impressive and might reduce the need for further editing. The lenstip site offers a range of lens reviews, including detailed info about a.) max. resolution and b.) 'optimal' aperture ("critical aperture", which is neither the smallest nor the largest one).

Wow thanks so much for this info!!! Thats great!