Photoshop CS driving me crazy, please help ...

01/27/2005 01:04:47 AM · #1

Having a small problem with Photoshop, its been bugging me for a while now, and I cant seem to solve it.

When I look in a files folder at a picture and hover the mouse over it, I can see the picture dimensions and size, for example one picture I have is the dimension of 639X640pixels, and size is 129KB. The problem is that when I open that same picture with Photoshop, and look at the image size in Photoshop(Image/Image Size), the pixel dimensions is 1.17M all of a sudden! The pixel dimension is still 639X640. Every picture is like this, when I open any picture in photoshop it's about 10X larger than it should be.

A tiff file which I saved in CS is 26M, and 2100X2100 pixels. When saving this image on maximum quality Jpeg and baseline optimized it is 13M in photoshop, but when looking at it in the files filder it is only 1.3M :(. Shouldnt a 2100x2100 Jpeg saved on highest quality be larger than 1.3M??

Whats going on?? I am sure its something silly, I just cant seem to figure it out.I used to be able to see the actual file size in photoshop.. I am running CS in Adobe RGB 1998, although changing it to sRGB did not make any difference. In color management I have set everything to preserve embedded profiles, it does not matter if I use the embedded profile, dont color manage or convert to color space when I open a picture.

Any help appreciated :)

animes2k

01/27/2005 02:06:15 AM · #2

Your "Image/Image Size" is the uncompressed file size. When you save it as a JPG, there's data compression going on (some data is being lost in this compression format), making the actual byte size of the file much smaller.

With TIFFs you have the option of saving with non-lossy compression, as well (no image data is lost).

So, your smaller file size is a result of data compression, while Photoshop is seeing the uncompressed data size.

Canon EF 17-40mm f/4L USM

01/27/2005 02:28:06 AM · #3

Ok.. But a 8M uncompressed Tiff file straight from the camera, shows as being 47M when opened in Photoshop, nothing done to the file, just transferred straight from Digital Photo Professional,(canon RAW workflow software)

Ivar

Canon EOS-7D

01/27/2005 02:58:52 AM · #4

Originally posted by Sonda:

That´s not the actual size of the photo.
That´s just the amount memory that Photoshop uses to have this photo open. Nothing to worry about.

Message edited by author 2005-01-27 02:59:57.

01/27/2005 03:14:28 AM · #5

Ah ok.. cool, thanks :) I thought it used to show the actual size there?

kirbic

Canon EOS R5

Canon RF 24-70 f2.8 L IS

01/27/2005 03:51:26 AM · #6

Since you're looking at the Image>Image Size dialog, I assume you mean at the top where it sez "Pixel Dimensions". That is not the file size, it's the number of pixels. If you have a 639x640 image, then to calculate the number of pixels you multiply 639 by 640 and get... 408,960. WTF?? Where does PS get 1.17M? Because Photoshop counts each channel as a pixel, so now multiply 408960*3 and you get... 1.227M! Still not the result that PS gets. The reason is that PS thinks a megapixel is 1.0486 million pixels. But why, you ask?! Some old timers may recall that a kilobyte was "defined" as 1024 bytes in the early days of computers, since it was an even power of two (and computers deal well with even powers of two, since they are binary machines). A megabyte, then, is 1024*1024=1.0486M bytes.
So ultimately, if you take (640*639*3)/(1024*1024) you do get 1.17M pixels.
This number is incredibly useless, since ...
A.) Megapixels have no relation to magabytes, and should not be counted that way. A megapixel is 1.0 million pixels.
B.) A pixel is composed of one or more channels, but is still one pixel. Unless we're Sigma's DSLR marketing team, we don't count each channel as a pixel.

TMI?

edit: end of chapter exercises

1.) If I take a 640x640 image and convert it to grayscale, how many pixels will PS report?
2.) If I take the same RGB (3-channel) image and convert it to CMYK, how many pixels does PS report?
3.) If Laurielblack sees this thread, will she compare me to Satan?

Message edited by author 2005-01-27 04:02:04.

01/27/2005 04:17:52 AM · #7

Awesome Kirbic, it all makes sense now. thanks!!

About my 2100 by 2100 jpeg.. I guess I could just add some layers to increase the file size if I wanted :)

Nikon AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II

01/27/2005 05:22:42 AM · #8

Wanted to share with those that might not know about this program... First time I ever heard of it, although it seems like it's been around for a long time.

It solved my "problems" .. Always seem to get something good out of being ignorant :)

Link

When saving my 2100x2100 tiff file in image optimizer as a Jpeg on max quality with extra color it comes out as 2.5 mb, and you can easily see the actual filesize in that program. Looking very good as well!

dacrazyrn

Nikon D300

01/27/2005 07:26:27 AM · #9

That program looks like it is mainly for web images. You have Photoshop, already?! Unless you are strapped for HD space, why jpg (besides for the web)?
If you ever really want to print your images, best to stay TIFF, PSD, or other lossless file type. Everytime you open and then save a jpg it is losing more and more data. Even the first save loses data. Lost data equals decreased image "detail" somewhere.
Why the obsessive-compulsion on file size? (C:

Koriyama

Nikon D200

Nikon AF Micro-Nikkor 60mm f2.8D

01/27/2005 07:33:23 AM · #10

Originally posted by dacrazyrn:

Everytime you open and then save a jpg it is losing more and more data.

This sounds much worse than it really is.

After we have finished working on a document, there's no problem in saving it as a jpg. If we ever want to print that file again, there's no need to resave it. Simply close the file without closing. This keeps the document at the same quality.

dacrazyrn

Nikon D300

Nikon AF-S DX NIKKOR 18-200mm f/3.5-5.6G ED VR II

01/27/2005 07:37:51 AM · #11

Just pressing the point that you LOSE data. Data loss bad, yeah. Wap...Wapner at six, yeah. (C:

Pentax SMC DA 18-55mm f3.5-5.6 AL WR

01/27/2005 02:15:05 PM · #12

I am not strapped for HD space,(having 2HD's 60gig and 250gig) I am always keeping the original RAW files, and put them on discs later when it gets filled up.

These Jpegs I wanted to make was for the web, the tiff file obviously being too large, and when saving in Photoshop as a jpeg, they were too small. This program can save a larger Jpeg with better quality than Photoshop can, and it shows you the actual file size at the top which is exactly what I wanted.

Message edited by author 2005-01-27 15:22:28.

drz01

Pentax K50

01/27/2005 02:26:22 PM · #13

Originally posted by Sonda:

Tiff files can be compressed also in fact most are but unlike jpeg's it is a lossless compression all the detail is restored when it is uncompressed. A tiff file is a bitmapped file and in most pictures there is spaces where areas of the photo is of the same colour/brightness etc. so this information can be compressed.
Look here for som info on file types and raw is bitmapped file too.