Brightening up rendered images

[craigball]

Hi whats the best way of brightening up my rendered images in PS, because when i come to print the final image it comes out loads darker than on screen.

 

Regards

[WAcky]

This is probably your workflow messing up your gamma. Not to worry.

 

When you render your image, save it in a 16 or 32 bit format (something like an EXR.) This will let you make more drastic changes than an 8 bit image without introducing bad degredation.

 

In photoshop use the image > adjust > exposure command. I think you need to input .4545 or 2.2. Cant remember which one but that will correct your gamma issue...

 

Good luck!

[craigball]

thanks mate!

 

whats the crack with exr? is it a masive file? i just save my images as jpg is that a big no no?

 

thanks for your help

[WAcky]

Well jpgs are a compressed format and work a bit like a VCR in that every time you save a jpg it will keep compressing and degrading the image. It's fine for a final image to post on the web but until that time forget about jpgs.

 

EXR is a "lossless" format, like a CDRW in that you can keep altering the content and saving out and the image will never degrade.

 

The reason you should work in EXR is that a JPG can only store so much information for each pixel because it only has an 8bit colour depth (see links below) whereas an EXR supports 16 (and i think even 32) bit colour depth. This means that each pixel holds waaaay more colour info and you can make more drastic changes in post (PS for example) like brightness and contrast changes before the image starts clipping and looking ugly.

 

Yes your files will be bigger and slower for PS to work with but in the end you wont be losing quality.

 

I think this info is correct but please correct me if im wrong anybody!

 

Some reading:

EXR format

Image bit depth

Lossy compression

Lossless compression

[craigball]

happy days. so after i have changed the image is there a way to save it as a jpg or some other file with less file size. because there are for presantation boards, and the exr file will slow work flow down loads?

[DavidR]

Exposure in Pshop will let you do an amazing amount of correction, vs using levels. The big thing is to use a 16 or 32-bit format like .tif, exr or hdr so you won't get banding in shadows and other icky stuff. You can then save your final image as an 8-bit .jpg, .psd, or whatever. Jpg is great for emailing, but not to work with. try this: in Phop, make a black square on a white background, flatten and save as .tif, and save a copy as .jpg maximum quality. Now use the magic wand to select just the black or white in the .tif, and you'll get what you'd expect; try this with your .jpg and your selection will be total crap, so use a lossless format for work, then save the output as a .jpg if you like.

[scottN]

is there a way to save a render as an EXR and work on it in photoshop? I've saved a render as an exr and uploaded it to cs2 but it wont let me edit it in any way.

 

Thanks, sorry for hijacking the thread a bit.

[WAcky]

I guess photoshop CS2 doesn't support EXR's. Never mind, just use Tiffs instead.

[scottN]

nah they do i just had to make it a 16bit image from a 32bit image

[WAcky]

This is a pretty annoying feature in PS. As the bit rate rises, the options in PS decrease. A lot of filters are unavailable in anything over 8-bit

[scottN]

yeah it is pretty weak, when i start working and get paid this summer i'm going to buy PROexr so i can bypass this problem.