Uprezzing, stair-step

[mercphoto]

I tend to agree with the people who run Smugmug that uprezzing an image is not necessary when sending prints to a lab like Smugmug. Maybe it is when making big prints at home, I don't know because I don't do it. But I know the common way to uprez is with Bicubic Smoother, going up 10% at a time. I was wondering, due to the nature of binary arithmetic, if going up 12.5% at a time would actually be better? Or is the inherint round-off error of a multi-step algorithm part of the pleasing effect (rather than doing the upsample all in one step)?

[cletus]

I tend to agree with the people who run Smugmug that uprezzing an image is not necessary when sending prints to a lab like Smugmug. Maybe it is when making big prints at home, I don't know because I don't do it. But I know the common way to uprez is with Bicubic Smoother, going up 10% at a time. I was wondering, due to the nature of binary arithmetic, if going up 12.5% at a time would actually be better? Or is the inherint round-off error of a multi-step algorithm part of the pleasing effect (rather than doing the upsample all in one step)?
Bill,

:dunno



Anyone picked up any good image processing algorithm books lately?

[ridetwistyroads]

All of that either went WAY over my head :bow, or way under. :scratch

[Shay Stephens]

I think the whole stair step process is bogus. I have yet to be able to see a difference between regular old bicubic resampling and all the other fancy shmancy* hoop jumping techniques *in a printed photo*. So in my mind, it's all a waste of time, and the extra steps are just there to make you think you are doing a more workmanly job.

The only time I need to upsample anything is when I am swapping heads on people and the head is too small for the body by a little bit (or similar scaling problems). All the big prints I send out are all sent native resolution, no matter how big I print.


*Fancy shmancy is a term I only pull out when I am rather worked up, uptight and outta sight on a subject. You will have to pardon me :wink

[mercphoto]

All of that either went WAY over my head :bow, or way under. :scratch

Very briefly, even though one-tenth is a rational number in the decimal world, one-tenth is irrational in the binary world. You cannot exactly represent one-tenth, the best you can do is approximate it. But you can exactly represent one-eighth in the binary world, it is "0.001". One-eighth is 12.5%.

[mercphoto]

I think the whole stair step process is bogus.

I figured as much. They touted this process as an absolute necessity at a Rocky Mountain School fo Photography weekend I went through. I kinda got the feeling that it was a left-over from the days of 1 and 2 MP cameras. That at today's resolution it was completely unnecessary.

[Shay Stephens]

Bingo! :thumb

I figured as much. They touted this process as an absolute necessity at a Rocky Mountain School fo Photography weekend I went through. I kinda got the feeling that it was a left-over from the days of 1 and 2 MP cameras. That at today's resolution it was completely unnecessary.