TIFF or JPEG?

[powerMarkymark]

I'm scanning photos into my computer with PhotoShop.
If I save in TIFF format the files are averaging 6500kb.
If I save as JPEG the files are around 2600kb.

I have not done this before, are there advantages to the TIFF format over the JPEG.

Hard disk space is not a factor, I have plenty.

Can someone take the time to explain the advantages/disadvantages of both.............or is there a better format to save in?


EDIT: Allright...........I see a consensus forming here.

JPEG is out.

I just tried saving in PNG format and it wants to know Interlaced options "None or Interlaced", any ideas?

Marc

Tnx.

Marc

 

[monzie]

jpeg's are compessable and therefore 'lossy'...every save will lose detail,,the higher the compression used the worse the problem. Advantages are highly conpressable (so much smaller files) making them just excellent for 'general' pc usage and internet work....but not so good for photo editing (each save reducing the quality) or quality work.

TIFFs are lossless (unless using say LZW compression.....but even then less than say jpeg). So roughly opposite of above...and the format was developed for scanners/printers/photo editing work in the first place.

 

[powerMarkymark]

Wow..........thanks for the quick reply.

Glad I was using TIFF format all this time.

I just noticed though I am saving with 8bit colour..........any noticeable advantage with 16bit?

Marc

 

[monzie]

32bit will have a higher colour range than 16bit (ie more 'shades' available of any given colour).

 

[BurnItDwn]

8 bit color kina sucks ... only 256 shades of color total ... If it's black and white ... or mostly text, it will be fine, however, otherwise you will want at least 16bit color.

 

[Sunner]

Even 16bit color is way too little for real pictures.
Of course it depends on what you're photoing, but most anything that's a bit colorful will show banding using 16bit color.

 

[drag]

Tiff images cause compatablity problems. There are a dozen or so variations of "tiff" formats, each vendor uses their own version for whatever reason. The only reason it is considured "standard" in the industry is because the different vendors go thru big pains to make sure that their apps can handle everybody else's slightly incompatable tiff formats without problems.

LZW compression can often cause picture file sizes to get BIGGER in some cases., which is funny.

Jpeg sucks because each time you save a picture as a jpeg it looses information. Open a file, edit it, save it as a jpeg, then do it again, and again, and eventually you'll notice that it begins to look pretty crappy. Jpeg is for final, finished products only. That's why it's called "lossy".

Well then what to use?

PNG format. Use that instead of tiff if you can. It's lossless, so like (most) tiffs you can re-edit it over and over again and save it over and over again with no loss to image quality.

It's a standard internet format, which means that everybody and their mom can view them, although IE (of course) screws up the transparencies.

It supports alpha channels for doing gif-like things like transparencies for websites and such. You'd use it for high-est quality stuff. It makes more sense then using jpeg at 90-95% quality.

Since it's open source it has nearly universal support in most vendor's apps and if you need it to be a tiff you can go from tiff to png to tiff with no loss in quality as long as you pay attention to what your doing and use proper save options.

Use the highest color (32bit usually) quality you can use for when your working on images, unless they need a specific color pallate for a specific purpose. You can always lower the color qualiity, but once that info is gone you can't get it back.

(take a 32bit image and make it 8bit. Looks ok. Take a 8bit picture and make it 32bit, i'll still look like it's 8bit image.)

Lots of people will say use tiff, I say use png, you use whatever your comfortable with.


File formats for images explained

 

[THUGSROOK]

a tiff file is the same size as a bmp.
only difference is that a tiff file can include "layers".

use bmp if you want an uncompressed full quality file.

 

[sciencewhiz]

Originally posted by: monzie

TIFFs are lossless (unless using say LZW compression.....but even then less than say jpeg). So roughly opposite of above...and the format was developed for scanners/printers/photo editing work in the first place.

LZW is lossless.

 

[powerMarkymark]

Allright...........I see a consensus forming here.

JPEG is out.

I just tried saving in PNG format and it wants to know Interlaced options "None or Interlaced", any ideas?

Marc

 

[drag]

a tiff file is the same size as a bmp.
only difference is that a tiff file can include "layers".

use bmp if you want an uncompressed full quality file.

OMG stay away from bmp, run away! run away!

Allright...........I see a consensus forming here.

JPEG is out.

I just tried saving in PNG format and it wants to know Interlaced options "None or Interlaced", any ideas?

Interlaced refers to the way the image is displayed on the internet if somebody is downloading it.

What would happen is that as the person is viewing the image as it's getting download:
non-interlaced:
The image starts at the top and slows grows down to the bottom until it is finished downloading.

interlaced:
The image starts at the top and quickly grows down to the bottom, but is very blurry, then it starts getting sharp at the top and goes down to the bottom, then again, and again until the image becomes fully rendered.

When interlaced the image is saved skipping several lines at a time, as it's openned it fills in the missing lines until you get full quality. That way a person can see the image completely before it's fully downloaded.

The downside to this is that it can make the file size slightly bigger. I don't think it has any impact on final image quality. Save it as a non-interlaced unless you want to stick it on the internet, and then only realy the finished product.

Oh and about Tiff:
Tiffs are lossless
Tiff are not compressed.
But...
Tiffs are lossy
Tiffs are not compressed
but...
Tiffs are lossless
Tiffs are compressed
but...
Tiffs are lossy
Tiffs are compressed.

Then there are variations on color quality, variations in compression scemes and other stuff. Lots of different formats that can call themselves tiffs. It's a format that was designed to be a universal solution, so no real standards about tiffs are accepted and it's impossible to enforce. Different vendors have different things they think is correct.

Of course if your working with photoshop, it's best to save them in photoshop format until the finished product. Then save a Tiff or a PNG for archival on cdrom or whatever, and then save another copy as a jpeg for display purposes, unless your going to do publishing then keep it as tiff. I don't know if png is widely accepted enough to fit the bill in a situation like that. Professional publishing is a very snooty type industry when it comes to stuff like this.