Elementary question - still need help

how to obtain maximum clarity

[contentmaster]

I have a large image (cover of a book) as a bmp file (742 X 1687 - image size when I open it in Photoshop) and I need to convert it to a much smaller sized jpg file(160 X 260). What is the best way of reducing it without losing clarity.

please help

[Don_Hoagie]

Wow, that's a weirdly shaped book.

Um, this appears to be a very simple question, though i'm not sure what do you mean by "clarity"...

At any rate, the issues of "dpi" and "resampling the image" in Photoshop might be of concern if you were talking about a print quality file, but this is a very standard, very small web image you're making here... just go to Image-->Image Size and convert... you'll need to crop to get those other dimensions. Then Save for web, and use "100 Quality" for the JPEG... virtually zero compression.

You probably know that already, but really there's no reason to overanalyze "clarity" when turning a large web-sized BMP to a small web-sized JPEG. Your dimensions for this new JPEG are too small for anything to really be an issue. The only problem would be if you compressed the JPEG file... but that's the same problem you'd have with any image for the web.

[collymellon]

The above suggestion is the most suitable solution - however I have achieved great image quality (sometimes better than photoshop) re-sizing BMP in editing apps such as MS Word..

[monkeythumpa]

I think I know what you mean, "sharpness". Resize it to the dimensions you want. If you are using Photoshop go to "filter" then "sharpen" than play with any of these filters. This will get rid of the blur that accompanies vast shrinking of images. It should have nothing to do with how you export it.

[Don_Hoagie]

Filter-->Sharpen will not RETAIN image clarity, it will simply add sharpness to the new image... it may make the image more appealing or less appealing, depending on the subject matter.... it may appear to look more like the original, but it surely is manipulating the image further away from what it originally was. If sharpness is what you mean by "clarity", then yes, this could be worth doing.

[contentmaster]

Yes by clarity I do mean sharpness ... the book cover has a lot of text written on it....after reducing the size the text - title and other important content is just not legible thus, destroying the whole purpose of the image.

Filter - Sharpen > using this once on the image did improve the sharpness a bit ...however using it more than once on the image made it less appealing ...

am I right in concluding that there will be some loss in sharpness when I resize a large image to much smaller proportions and Filter - Sharpen is about all that one can do in an effort to improve it to some extent?

[Beagle]

I don't use photoshop, but I often resize large images to much smaller ones. I've found it usually helps to lighten the picture some and increase the contrast, in addition to sharpening. A lot of times I find the same result as given here: sharpening once is good but sharpening twice is too much. In that case, increasing the contrast instead of that second sharpening often helps. I can't give any specific settings, as each image is different. You just have to play with it.

[monkeythumpa]

Yes, when you shrink an image you compress the information associated with it. In the print world this is not a problem, in fact it usually improves image quality since resolution on an analog machine can be unlimited. The problem is with the web.

The average human can interpret about 150-200 dpi at 1 foot away and since monitors only display at 72-96 dpi you should be able to notice a degradation in quality. The reason is that each pixel needs to account for a greater area of the image. Since that pixel now needs to be an average of the color values you will lose some information and "clarity" especially where the pixels join. The "sharpen" filter and to a more precise extent "Unsharp mask" filter will improve the percieved "clarity", but after a certain point you won't be able to squeeze any more information out of a low resolution image.

You can think of it like a mosaic. The smaller your tiles, the more accurately you can reproduce a picture. But if you only have big tiles, the picture has to be a lot bigger (and the people looking at it have to stand further away) to get the same sort of resolution. On a computer the tiles are always the same size no matter how big or small the image is.