Upscaling (resizing)

[MX5]

Not something I've done but a friend was asking about the process of converting say a 10megapixel image into say a 15megapixel image by 'upscaling' ... by interpolation. A couple of questions:

• Is bicubic 'best' ?
• Will photo libraries such as Alamy baulk at these upscaled images ?
• Is there a better method.

These might seem naive questions but as I’ve never done this I couldn’t help my friend.
So anyway who can point me in the right direction will get a gold star ;-)

Thanks in advance.

[Canon-Fodder!]

Re: Upscaling (resizing)

Hello MX5;

I've tried a few large-scale upsizes with various degrees of success... Some work; some don't. Much depends on the volume of fine detail in the image. Landscapes tend to apply better than architectural detail for example...

First lesson I learnt was to NOT do it in one bash; a series of upsizes, c.10% increments a time, works much better...

Bicubic Smoother tends to work better for upsizing, Bicubic Sharper for downsizing

Can't help on the image library question...

HTH...

[malkie9]

Re: Upscaling (resizing)

Not something I've done but a friend was asking about the process of converting say a 10megapixel image into say a 15megapixel image by 'upscaling' ... by interpolation. A couple of questions:

• Is bicubic 'best' ?
• Will photo libraries such as Alamy baulk at these upscaled images ?
• Is there a better method.

These might seem naive questions but as I’ve never done this I couldn’t help my friend.
So anyway who can point me in the right direction will get a gold star ;-)

Thanks in advance.

There are certain image quality standards that Alamy apply . Hear is the link http://alamy.com/contributor/help/prepare-images.asp .

An extraxt from Alamy page on upsizing:

When an image file is increased in size, software has to 'create' extra pixels to fill the gaps. It does this by estimating the brightness and colour of the new pixels, based on their neighbouring pixels. There are specialist software packages and techniques available, some methods are more successful than others. We require scans to be un-interpolated and digital camera files to be interpolated up to 24MB. If you have a camera that is capable of producing an uncompressed 8 bit, TIFF file size of over 24MB then leave it that size. If you need to interpolate your digital camera files you must ensure that you use a professional software package, such as Abobe Photoshop.

They are very chosey also on the camara that has taken the shots. There is a list of acceptable cameras on their web site. My last camera was a Sony and they would not accept images from it so it was a great excuse with the missus that I had to buy a 5D MkII.

Slàinte,

Malkie

[Trevoreast]

Re: Upscaling (resizing)

They are very chosey also on the camara that has taken the shots.

yeah You need at least a 350D

No upscaling is required for anything from a 350D upwards.

Uncompressed file sizes of more than 24MB. This means you should make your JPEG file from an 8 bit TIFF file that is at least 24MB. If you have a camera that is capable of producing an uncompressed 8 bit file of over 24MB then leave it that size.

Trev

[EOS_Jim]

Re: Upscaling (resizing)

Why would the OP's friend want to upscale? is it just for Alamy?

[MX5]

Re: Upscaling (resizing)

Why would the OP's friend want to upscale? is it just for Alamy?

No I was just giving Alamy as an example (i think it was referenced on the forum recently ... so its the only library I have heard of .. me blushing).

I think the friend wants to go semi-pro (if that's correct English) ... as he's not got a job (and age means he will not likely get one) ... he's just putting his little toe in the ocean. I've told him it will be harder work than he's done for decades. I think he still uses Medium Format film (as well as DSLR) ...

Oh and why does he want to upscale ... well I gather someone told him size was important !

[EOS_Jim]

Re: Upscaling (resizing)

A 10Mp image can be printed bigger than he would probably ever need without any upscaling. I've a 20" x 30" print from a 20D 8Mp camera :)

Obviously some libraries have a minumum requirement and in those cases you meay need to don something but upscaling is something I very rarely do.

[MX5]

Re: Upscaling (resizing)

Okay all - thanks all.

I don't think I've ever done it myself ... may have played when doing a PS tutorial ... hence the question here.

He's aware of the QA rules that libraries apply.

[Trevoreast]

Re: Upscaling (resizing)

Buyers are aware of dimensions/ limatations, if they want to buy it, and use it very large, upscaling is their problem - not yours.

On a pic taken with smaller mp or "lesser" camera, it is probably more important to compose image carefully in the camera.
Much of the QC is about weeding out huge over processed crops, as anything else.
Some stock agencies don't allow sharpening, therefore if you're going to give your image a sneaky sharpen anyway :tongue:
It's best to do it at 100% magnification on your screen and err on the conservative side.

Trev

[daniel-obyrne]

Re: Upscaling (resizing)

Most Photo agencies will not accept up scaled images as they may be stolen work.. Reputable ones like the Raw files or full sized Tiff