Question about enlargement

[Bobobird]

A friend asked me if it was possible to scan a 4x6 pic of his family and produce a larger, printable version - probably in the 16x24 range or higher. He only has the print and cannot find the negatives.

Would appreciate some advice on which would be the best software to do the enlargement with or should I just let the scanner do it?

Thanks.

[Geoff F]

It is possible, Bobo. Just set the scanner for a high number of pixels. But can you do that with your scanner?

I would scan for 5,000 to 7,000 pixels on the long side. Either set the scanner to produce the finished size or set for the original 'size' but at a high resolution which you then resize with your photo editor.

I usually use the second option.

Also, some question over whether you use a little sharpening during the scan or do it all afterwards. As with a normal image.

The method is exactly the same with a negative. But you need to add more pixels because your starting point is smaller.

This does assume that the print is good quality, otherwise there will be some loss of detail. But a large image will probably be viewed from a greater distance so it might still work OK.

[Bobobird]

Thanks Geoff.

My scanner is old but can do pretty high resolution.

I will try both methods that you suggest.

[Manfred M]

Be careful when reading your scanner's resolution numbers. Some of the ludicrously high resolution output numbers are achieved through interpolation. Scan at the highest native resolution (this should be in your scanner's manual). Try to clean the crap off the flatbed. Mine seems to attract all kinds of dust that seem to show up until you look at the scanned image. You don't want to spend more time than necessary spotting out the dust...

[pnodrog]

At 16x24 I think you will disappointed. Hopefully the original photograph is well printed on gloss paper and is in excellent condition. Try scanning at a max of 1200dpi I think anything higher will only emphasis any texture or faults in the original. (In practice you will probably get little improvement by scanning above 600dpi) You should get plenty of advise by doing an internet search.

If you get lucky and adjust the scanned image to maximize its quality it may look acceptable as a 16x24 canvas print but probably not as a glossy premium paper print at that size.

Good luck - if it is an important family photograph at least you will make a needed backup copy.

[loosecanon]

Depends if the original printing was by film onto photographic paper, in which case the original may (or may not) have a surprising amount of detail in it. Unfortunately some anologue printing as done as "sharp as needed" for the print with speed rather than negative flatness being important.

If it was digitally printed or from a digital file it will be less sharp. probably 600dpi maximum.

A look at the print with a 10X magnifier will give you an idea of how sharp the original is.

Having copied the original you will then need to process it to increase the number of pixels, with your choice of software. You may then need to consider noise reduction and possibly removing any mosaic patterns from digital printing. Then adjust the size to exactly that you are going to print at (taking into account borders and so on). Then apply sharpening whilst looking at the sharpening effect. The aim is to make the image which may be quite soft appear sharper but to avoid introducing artefacts which show when printed.

A thin narrow border around the image can make it appear sharper.

Finally consider using a textured paper.

I have often used 6"x4" prints as the starting point for A3 display prints in technical exhibitions.

[Bobobird]

Have yet to see the pic, but it is a film print.
Will try out the various suggestions here and post back if I hit a hurdle.

Thanks everyone for the assistance.