How to Lose Your Web Viewers!
© 2000 by Walt Howe
(last revised March 21, 2000)
CONTENTS:
Introduction
Table of Download times
Table: How quickly they leave!
Comments
Suggestion Form
Introduction.. While catchy graphics make your web page or message boards attractive and get the viewer's interest, many graphics have the opposite effect. For every 10 seconds it takes for your graphics to load before your page contents can be seen, you risk losing 20% of your remaining viewers. This article, a companion to the "How to Create Small, Fast Loading Web Graphics," tells you how to be sure to lose your audience!
The problem is at its worst when you allow HTML in signatures in a message board, and people fill up a discussion with big signature graphics. One signature with a 60K graphic is bad enough, but suppose there are 20 of them in a row? It happens, and you need to manage it.
Download times. The following approximate download times will show you how long it takes to download a 1 megabyte page at different speeds. Yes, I have seen web pages with 1 meg and more of graphics files in them! If you were a net pioneer (anyone who has been online for more than three years), did you ever see the wonderful Vatican exhibits or the Dead Sea Scrolls when they were first posted? They were a wonder, because there was nothing else like them. How many times did you visit? How long did they take you? I remember starting a download of one graphic using the old Mosaic browser and waiting 20 minutes for the picture to appear on the screen. Today, the files are a lot smaller on those sites. They learned what to do to keep their audience. So can you!
| Transfer Speed | Transfer Time |
|---|---|
| 1200 bps | 2.4 hours |
| 2400 bps | 1.2 hours |
| 9600 bps | 18 minutes |
| 14.4 Kbps | 12 minutes |
| 28.8 Kbps | 6 minutes |
| 33.6 Kbps | 5 minutes |
| 56 Kbps or ISDN1 | 3 minutes |
| 128 Kbps or ISDN2 | 1.4 minutes |
| T1 or cable or ASDL (approx. 1500 Kbps) | 7 seconds |
| T3 or 45000 Kbps | .2 seconds |
TECH NOTES: Data is usually expressed in Bytes (B), and transfer speeds are usually expressed in bits (b), because it sounds like more. Nominally there are 8 bits in a Byte, but it doesn't stop there. Added to the transmitted data bits are bits used for overhead to ensure that packets of data are received correctly and reassembled in order. These are transmitted along with the data. The bits passed in a transfer are, therefore, more than 8 times the Bytes of data. For these tables, I have used 10 transfer bits per data Byte as an approximation. If you have a better figure, use it.
How Quickly They Leave! Using our rather subjective assumption that you lose 20% of your audience for every ten seconds they have to wait to see the page, the following table shows you how long it takes you to drive them out. The black figures are the seconds it takes to transfer a page of the given total size. The red figures are the percentages of viewers remaining after the files are transferred. Remember that the transfer times are under ideal conditions, and how often do you see ideal conditions? In real life, they are usually slower.
| sec % here |
10 KB | 20 KB | 30 KB | 40 KB | 50 KB | 60 KB | 70 KB | 80 KB | 90 KB | 100 KB |
|---|---|---|---|---|---|---|---|---|---|---|
| 1200 bps | 83 17% |
167 3% |
250 -% |
333 -% |
416 -% |
500 -% |
583 -% |
667 -% |
750 -% |
833 -% |
| 2400 bps | 42 42% |
83 17% |
125 7% |
167 3% |
208 1% |
250 -% |
292 -% |
333 -% |
375 -% |
417 -% |
| 9600 bps | 10 100% |
21 64% |
31 51% |
42 42% |
52 33% |
63 26% |
73 21% |
83 17% |
94 13% |
104 11% |
| 14.4 K | 7 100% |
14 80% |
21 64% |
28 64% |
35 51% |
42 42% |
49 42% |
56 33% |
63 26% |
70 21% |
| 28.8 K | 3 100% |
7 100% |
10 80% |
14 80% |
17 80% |
21 64% |
24 64% |
28 64% |
31 51% |
35 51% |
| 33.6 K | 3 100% |
6 100% |
9 100% |
12 80% |
15 80% |
18 80% |
21 64% |
24 64% |
27 64% |
30 51% |
| 56 K or ISDN1 |
2 100% |
3 100% |
5 100% |
7 100% |
9 100% |
10 80% |
12 80% |
14 80% |
16 80% |
17 80% |
| 128 K or ISDN2 |
1 100% |
2 100% |
2 100% |
3 100% |
4 100% |
5 100% |
5 100% |
6 100% |
7 100% |
8 100% |
| T1 or cable or ASDL |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
1 100% |
1 100% |
1 100% |
| T3 | - 100% |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
- 100% |
Comments. Decide where your typical viewers fit on the chart above. Are they likely to have high speed connections, or are they connecting at 28.8 Kbps or below. Keep the size of your pages where you will retain 80% of your viewers or better. Here are some reminders of what to do to minimize loading time.
- Don't put heavy content on your main page. Keep your main page small and link to the content on separate pages. Break those pages up into multiple pages, if they will take a long time to load.
- Keep the files as small as practicable. Review How to Create Small, Fast Loading Web Graphics.
- Always use height and width tags with graphics, which allows text to appear before the graphics finish loading.
- Use 72 dot per inch resolution.
- Use JPEGs for photos or pictures with a full range of colors, and use low quality. It is a misnomer, and it usually looks fine.
- Use GIF files for solid colors, text art, cartoons, and poster art, and use as few colors as possible.
- Don't allow posters to your message boards to use huge signatures. Publish your policy and enforce it.
Comments? Was this article useful to you? Do you have any questions, comments, corrections, or suggestions for improvement? Leave us a question or a comment in the Publishing on the Web Message Base or complete the Form below.
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