[Liz]

Currently doing a photo book with no prepared template. You know those ones, either the software you can buy or some kiosk tempation - all of which are a little design limiting. But at least you can drag and drop your photos into the prepared spaces.

In my current scenario, what I've done is loaded the photos into an A4 page as smart objects then transformed them to fit the spaces I have on the page. Ouch! I have some concerns with what I'm doing.

I mean, I understand that the original image needs to have the pixels to enlarge it, eg 6x4 to 8x12, but I got the impression from a workshop with a guru in Restoration in the US that with smart object I could just drag the handle and enlarge a 6x4 to suit an 8x12 page? Was I sleeping or misinterpreting the message maybe? Any comments I would appreciate. Horrified pixel specialists are most welcome. .

I have printed some of this stuff on an Epson R800 and surprisingly they seem quite OK.

So I guess my real question is - what is the magic of a smart object and what is it limits.

[mistermonday]

Liz, when you create a Smart Object, Photoshop stores the original image with all its pixels and works on a virtual copy. When you downsize an image normally Photoshop discards a proportional number of pixels and when you upsize it looks pretty bad because the orig data is gone. With Smart Objects, when you enlarge the image, Photoshop goes back and does the re-sizing from the orig image with all its pixels. In fact if you perform multiple changes on the smart object Photoshop runs those changes or filters on the cached original. The only downside to smart objects is they slow Photoshop down because of all the extra work Photoshop is doing in the background. This is not noticeable on small or medium size images. However, if you have very large files you will likely notice slow performance. But that may be a small price to pay for not having to redo parts of your workflow multiple times and for not having to have a hole bunch of extra merged layers which take up more memory and also tend to slow Photoshop down.
Regards, Murray

[ktg222]

Murray,

It is my understanding that if you upsize a smart object beyond it's original size degradation of the image occurs; in that, making the image larger than its original size more pixels need to be added to make it the larger size. But if one makes the image smaller than its original size no degradation occurs and you can manipulate the size ad infinitum as long as you do not go larger than the original. Yes?

k

[mistermonday]

K, yes, correct. Regardlesss of smart object or not, whenever you upsize to a greater number of pixels than was in the orig image, you are manufacturing pixels through a process of interpolatation.
Regards, Murray

[Dave.Cox]

Unfortunately Murray is correct. When you increase the size of a photo more than the original size, or more that the current data set, you add pixels (That's what interpolation means, to add in between.) Adding new pixels does not add clarity, since the new pixels that are added, are made to match the existing pixels While this will fill the holes, it doesn't add clarity. You can only work with the information that you have. This is what we refer to as a loss of resolution. Sometimes it's referred to as pixelated, as you can start to see the square pixels. In the old days of film enlarging used to make a photo look grainy, do to the way the particles in the film made up the photo.

[TommyO]

k,
We should clarify that degradation occurs when upsizing AND when downsizing. Although minor changes in size either way tend to look fine, it is when you make dramatic changes in size either way that the degradation becomes readily apparent. The reasoning is the same when downsizing. The algorithm must decide which pixels to toss out. The smaller you go, the more that must be tossed. Eventually, the image becomes extremely jagged, or pixilated. To see it, just zoom into any of the images posted on this forum. You don’t have to zoom far before you see jagged edges in the image. These were not there on the higher resolution images, but are a result of both downsizing and then compression using the jpeg format.
Tommy

[Kraellin]

this is not, strictly speaking, a 'restoration' question, so i'm moving it to the photoshop forum.

please make your posts in the appropriate forums.