login   |    register
Photography
Questions about shooting your models and dioramas? Ask here.
Simple photo editing question
MartinJK
_VISITCOMMUNITY
British Columbia, Canada
Joined: January 17, 2006
KitMaker: 59 posts
Historicus Forma: 0 posts
Posted: Monday, January 23, 2006 - 01:42 PM UTC
Hello.
Recently I have been trying out the digital camera. The digital camera I currently own makes pictures at minimum of 1024x768 resolution. I figured that the pictures at that resolution are a little too big in scale to be efficiently posted on here. Trying to use IrfanView to scale down the pictures from 1024x768 to 800x600. However, the resampled pictures at 800x600 are bigger in file size (from around 130KB to around 350KB) than the higher resolution counterparts. Both are Jpeg files. Now, the only thing I change in IrfanView - aside from the resolution of the original picture - (for those who are fimiliar with the program) is while saving the resized picture I slide the 'picture quality' from 80% to 100%. I figure this would a impact of the file size, however like I stated earlier, should the edited 800x600 picture be twice as big as the original 1024x768 picure?
I hope this makes sense.
Thanks for your time.

Martin
jazza
_VISITCOMMUNITY
Singapore / 新加坡
Joined: August 03, 2005
KitMaker: 2,709 posts
Historicus Forma: 0 posts
Posted: Monday, January 23, 2006 - 03:26 PM UTC
Hi Martin,

I often scale my photos down before placing them up here however i dont use the software that you speak of. I personally use JASC Paintshop Pro to resize which ultimately reduces the file size of the image. Some photo editing software do apply filters etc which do end up increasing the file size but certainly not by the amount you mentioned.

I would advise that you try either Photoshop or Paintshop when trying to manipulate your pictures from your digital camera.
nzgunnie
_VISITCOMMUNITY
Auckland, New Zealand
Joined: October 15, 2004
KitMaker: 371 posts
Historicus Forma: 59 posts
Posted: Tuesday, January 24, 2006 - 09:59 AM UTC
It is normal, the same thing happens in photoshop. It is all to do with the amount of compression applied by the camera compared to the amount applied by your editing software. When you 'save as' the software re-interpolates the image, and compresses it at the setting you have selected. This may be considerably less compression than what was applied by the camera.

What you have changed is the level of 'jpeging' that has been applied to the file. That is the ammount of compression.

Just 'save as' your 800x600 file again but at a lower quality setting.
MartinJK
_VISITCOMMUNITY
British Columbia, Canada
Joined: January 17, 2006
KitMaker: 59 posts
Historicus Forma: 0 posts
Posted: Sunday, January 29, 2006 - 05:28 PM UTC
Thanks for the input guys. While reading some on the internet, I think that I got the basic understanding of Irfanview and figured out how to reduce image size.


Martin
adws
_VISITCOMMUNITY
Texas, United States
Joined: June 02, 2003
KitMaker: 37 posts
Historicus Forma: 0 posts
Posted: Thursday, February 02, 2006 - 07:23 AM UTC
also one thing you need to make sure is that for saving photos for the web they only need to be at 72 dpt. By reducing the size from 1024X768 to 800X600 @ 72dpi should decrease the file size reguardless of what software you use.

But to tell you the truth 800X600 is still probly a little too big. You can descres the file size even more by croping the image to 600 pixels (px) in width and whatever size the height comes out. Just make sure you scale it down evenly.

If you take a look at my photos, they are all at 600px in width saved at 72dpi with a jpg compression of 6 in photoshop. And I think they look very good. Now I did take the photos with a canon 10D which shots the photos about well over 3,000 px wide at 180dpi. You might want to try saving your compression at 75 or 80%.

Here is a link to my photos
http://photos.kitmaker.net/showgallery.php?cat=500&ppuser=2733
nzgunnie
_VISITCOMMUNITY
Auckland, New Zealand
Joined: October 15, 2004
KitMaker: 371 posts
Historicus Forma: 59 posts
Posted: Saturday, February 11, 2006 - 04:05 AM UTC

Quoted Text

also one thing you need to make sure is that for saving photos for the web they only need to be at 72 dpt.



Remeber that most moinitors display at 96dpi now, not 72.

Regardless, the dpi is only relevent when you specify a size in inches or cm. When you specify a pixle dimension, your monitor will display the image at that many pixles regardless of the 'dpi' setting you have selected.