What to do with an ugly old pipe!

[Abitconfused]

First my apologies for so grotesque an image that rests among so many esthetically more desirable images. But, alas, this is my favorite old pipe and it has served me well. I use it to test lenses and techniques.

The original image was taken with a Nikon D7000 using the 17-55mm f/2.8 lens (ISO: 200, f/9, 1/500s at 38mm). The original size of the image was 82 megabytes (19" x 13" at 240 PPI) (483mm x 330mm). I adjusted lens distortion and chromatic aberration in RAW (Photoshop CS6). I also adjusted highlights and shadows and added some vibrance and clarity. Some other enhancements (Curves, Saturation and Sharpening) were added with moderation using Photoshop.

Next I reduced the image size to 10" x 6.6" (254mm x 166mm) at 160 PPI to create an image 9.7 megabytes small. Then I used "File < Save for Web..." and applied the color assignment option to obtain an internet friendly sRGB color space and chose to create the JPEG file at "Very High" compression for a 600k file size. This is my technique for conversion to internet images. The file has, I believe, very good detail for a 600k image and endures magnification quite well for an image this size. I think this may be because the color characteristics of the image are very close to ideal. Whites are white, grays are gray and blacks are, pretty much, black.



Your critique of this technique for creating compressed images is appreciated.

[Black Pearl]

Don't bother setting a ppi when you size your images to 19"x13", just leave the original pixel alone.
When you size for web simply set the largest edge you want - i.e. 1000 pixels and save it normally.

[xpatUSA]

Good old American pipework, never noted for its beauty - but with a certain charm, nevertheless! Quite a difficult subject, I would have thought.

I do note the dreaded halos at high-contrast edges indicating some enthusiastic sharpening in post. I personally believe in sharpening after down-sampling, not before, because the act itself of down-sampling can increase the acutance of an image.

"an image 9.7 megabytes small" . . hmmmm . . the times, they are a-changing . .

[RustBeltRaw]

I don't understand why people use DPI and physical dimensions to specify image size. If an image is displayed digitally, it doesn't really have a "size" in the traditional meatspace (outside of computers) sense. Robin partially explained this. Basically, the computer doesn't care how many inches at how many DPI a photo occupies, since monitors only know how many pixels they have, not their own measurements. AKA, the DPI of a given monitor is constant, so all it cares about is the image's resolution (pixels). If you're sizing for web, there's no need to fiddle with the DPI or dimension settings - they're irrelevant in the digital realm. Photoshop frequently asks for those dimensions because it assumes you're making prints instead of prepping for web display.

Personally, I use a 900px maximum dimension (height for portrait, width for landscape) size for my web images, and either the bicubic or bicubic sharper reduction algorithms in Photoshop's resizing utility (Ctrl + Alt + I). If you sharpen an image before downsizing, the bicubic sharper frequently yields and oversharpened downsized photo.

[jcuknz]

Since I work with Paint Shop Pro and have mostl;y since starting there are two stages to producing a web image. First stage is resizing down to the pixel count I think most likely to be suitable for my viewers monitor.... originally around 800 as the widest dimension, 700 pixels for Photo.Net and usually the same when sending to my family who use laptops. Email programmes waste quite a lot of the monitors capacity with information across the top and down the side so if you want to save the recipient scrolling then downsize to suit them.

The second stage is compression ... for family web exchanges there is little to be gained with files larger than 40<50Kb and PN has a 100Kb limit if you want the image to go with the text instead of as a link. That was in dial-up days but I admit to getting lazy now I have broad band and know my receipients have it too. PSP makes the compression stage very easy to do though is quite separate from re-sizing. [ File/Export/JPG optimiser [ or GIF or PNG ] if any PSP user hasn't found this yet ]