An attempt at photography

I just put some pictures I took while on vacation on my site. So anyone who is remotely curious about what I look like -- click on the URL below ;)

Mike Quinn wrote:

Um, Mike, can I make an eensy suggestion? Next time, convert the photos to GIFs... the photos on your site are just waaay too big to view easily. 400k+ each eats a looot of bandwidth. If you convert 'em to GIFs, they should shrink down to about 125k. Oh, and set the resolution to 72 dpi-- that's the best res you'll get for web purposes.

Still waiting for the page to load, rich.

Jane: All I want is to make beautiful things!

In article , [email] wrote:

Actually, .jpg is better for photographs, as 1) .gifs only have 256 colours, and 2) a 256 colour .gif can sometimes be bigger than a .jpg of the same size. Monitor resolution is 72dpi, so anything bigger just takes up space. 400K /is/ way too big.

As I type this, I haven't actually seen the pictures yet. Rest assured I'll be back to offer more suggestions

Thinking of which. Suggestion: make two versions of each picture, a tiny thumbnail image, which links to the actual image. That way, you have a single page with, say, a dozen, tiny, quick loading thumbnails, which then each link to the corresponding larger image.

Can you tell I do this for a living?

www.nmgm.org.uk

I designed the floorplans for Liverpool Museum and the Walker Art Gallery, and have done grunt-work on several other pages. The Maritime Museum's Transatlantic Slavery pages should be live soon, either today, or next week.

In article ,

Okay I'm back, analysis follows. "Here comes the science bit; concentrate." (5 points)

When I first looked at the pictures page, I saw a long line of little pictures, and thought "D'oh! Mike already knows about thumbnails." But then I looked again and saw the browser was taking time to load down a 400+K image, which on-screen was only about 25 pixels square. This is a bad thing. An 884pls x 553pls, 460k image is still 460k even if it's resized in a page of HTML down to 50pls x 50 pls. Make two images, one large and one small, and use the small one as a link to the larger one.

I grabbed a copy of logo.jpg, and uwave.jpg, so I could have a look at them.

uwave.jpg is 150dpi, 884 X 553 pls, and 460K. Dropping it down to 72dpi, makes it 424pl x 265pls, _18.2K_. Hella more manageable.

I converted the smaller uwave2.jpg into a 256 colour .gif. The picture quality drops (colour banding, instead of smooth transitions), while the size is 49.2K.

Similarly, logo.jpg is a whopping 150 dpi, 1271 x 654, 721K. Dropping it to 72 dpi makes it 610 x 314, 24.6 K. And that's still in colour. Making it a grayscale will reduce the size further, and turning it into a 5 bit .gif will make it smaller still. Heck, 4 bits even.

To summarise:

When saving the final version of an image, save it at 72dpi.

If the photograph is black and white, change it into a grayscale image.

Photographs should be saved as .jpgs, while images with only a few colours can be saved as .gifs. If the software you're using allows it, check and see how many colours are used before converting the image. Sometimes an image with 250 or so colours is better off saved as a .jpg (eg 256 colour grayscale images...)

If you don't already have it, get Paintshop Pro, but bear in mind it's Shareware. If you can afford it, get Adobe Photoshop*.

Guess that's it for now...

The dpi setting should be irrelevant, it's only taken account of when printing an image. It's the size in pixels that's important for on-screen usage. When sizing pictures view them at 100% size (1:1) and crop or scale them accordingly. For web usage 600x800 is probably as big as it's advisable to go, as that seems to be the most common display setting these days.

The thing about monitors being 72dpi is also something of a myth, it depends on your display setting. Early Macintosh monitors were 72dpi, whilst Windows assumes 96dpi (except when you're running software which originated on Macs, such as Photoshop...) The only way to really know your monitor dpi is to measure it's physical width and divide it into the number of pixels. My monitor is currently at 90dpi but at some resolutions it's 100dpi (which is the "native" resolution of the phosphor dots on it) and at others as low as 50dpi.

(Because of all this, Photoshop's option for displaying pictures at their so-called "print size" is basically useless, as it always assumes your monitor is 72dpi and thus typically shows pictures much smaller than they would be printed, eg. 4/5 life size on my 90dpi monitor.)

With jpeg compression it's worth playing around with the quality setting as for some images it can be dropped quite low without much loss of image quality, whereas for others it needs to be quite high. All the images on my website have been individually compressed at a setting that gets them as small as possible whilst retaining as much quality as is warranted by the use I'm putting the pic to. In the section showing my own photos I've used a higher quality setting than most places on the site but the jpegs are still only 60K on average.

My Daria section tends to use 16 colour GIFs for maximum compression, eg. the big image of Daria scowling is only 30K. This is possible basically because cartoons use a limited palette or colours and large areas of smooth tone (if you can remove the noise and ghosting that Channel 5 adds!).

The advantage of a GIF over a jpeg is that the picture will be sharper and artefact-free, as long as it doesn't have more than 256 colours such that it requires dithering. A lot of websites tend to use jpegs for logos and headings when they could get smaller files and sharper lettering using a 16 colour GIF. I suspect a lot of the blame for inappropriately encoded image files lies with the default settings of people's software being inappropriate.

-Shez.

On Fri, 6 Aug 1999 20:06:38 +0100, Shez wrote:

Fight patented algorithms! Fight GIF! Use PNG (better compression and supports truecolor). MSB

On Sat, 07 Aug 1999 20:38:36 GMT, [email] (Matthias Benkmann) wrote:

Perhaps, but GIF is still pretty much a universal standard. Until PNG becomes much more common, I don't see GIF going anywhere.

Martin
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On Sun, 08 Aug 1999 00:34:18 GMT, [email] (Martin J. Pollard) wrote:

PNG will become more common when more people start using it DESPITE the fact that it's not as common as GIF. Since modern applications and browsers support PNG, there's no reason not to use it. MSB

MSB wrote:

Depends on what you mean by modern. My copy of Communicator 4.0 doesn't like them, for instance.

Len

On Mon, 09 Aug 1999 20:32:36 GMT, [email] (Len Pitre) wrote:

Strange. I got the standalone version of Netscape 4.07 and it displays PNGs just fine. MSB

On Mon, 09 Aug 1999 18:11:18 GMT, [email] (MSB) wrote:

Ah, but "modern" is a very subjective term. Can you guarantee that all "modern" browsers support PNG, on platforms other than Intel and Mac (i.e. Unix, Linux, etc.)? You can't, but you can with GIF and JPEG.

I have nothing against PNG, and I hope it does someday become the accepted standard. Until then, however, I have to think about serving as wide an audience as possible, and I can't do that with PNG. Unless I want to equate "cross-platform" with "Windows," as Microsoft wants me to do. :-)

Martin
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On Mon, 09 Aug 1999 23:02:00 GMT, [email] (Martin J. Pollard) wrote:

Don't worry about Unix. Lynx supports PNG like it supports all other image formats. And doesn't every serious Unix user use Lynx :-) Fun aside. I would wager my life that XEmacs supports PNG, too. XEmacs has EVERYTHING. I'm sure it even has The Bomb. MSB

In article ,

Thanks, i'll see what i can do (now you see why I've only had text so far -- image processing isn't exactly my area)

I knew in the back of my mind that some people would have trouble with them, so I apologize to everyone still waiting.

HMM vacation photos. Next will be posting links to pictures of our kids.

But not me of course. Those pictures of my kid are on the internet are stricktly for family only. (don't you feel lucky?)

Bear wrote:

Yes, but not everyone has image editing SW that can change res from 150 to 72 dpi. I figured I'd offer the expedient of converting to GIF instead. You're right, though-- I've got a lot of photos from my digital camera that are much smaller as jpegs than as GIFs-- they're both lossy codecs, depending on the image and the SW you use.

rich.

Quinn: I can't be a brain! My friends will hate me!

Damn it, man! Where's the porno? ;)