Maddog 'n' Miracles -- Photos & Netscape


Notes on Viewing Scanned Images for Netscape Users

These images were scanned from photographs, using a Mustek CG-8400 Color hand-scanner in the "super-color-graphics" mode. In this mode, the scanner provides an 8-bit (256 level) conversion for each of the three primary colors (Red, Green, < B>Blue). So scanned, it would take a color pallette of 16 million colors to provide an exact replica of the scanned image. If you have a graphics card and driver which will provide this resolution, great! Otherwise -- like me -- you will be settling for some amount of compromise in picture quality.

My system (Dell 386SX12 with 512K video memory and a Dell VGA Color monitor with 640 x 480 resolution) is anything but state-of-the-art, yet very capably reproduces these images, which look bright, colorful, crisp, and smooth on my display. If I can do i t with my equipment, you can surely do it with your hot-stuff PC.

Any system with a 256-color pallete should be capable of reproducing these images with near photo-like viewing quality. However, I offer a few tips for those having problems:

1. For 256-color operation, your system will need at least 512K video memory (not system RAM) for a 640 x 480 VGA display, and at least 1Meg for an 800 x 600 SVGA display. Higher resolutions will need correspondingly higher amounts of video memory. Vid eo memory is typically installed on the graphics controlller card (although on my system it is built-in to the motherboard). If you do not have enough video memory, your system will (probably) only support a 16-color pallette. This will still allow you to view images, but the viewer software will be required to "approximate" the finer-colors by either substituting the closest available color from the 16-color pallete, or "dithering" (using multiple dots of the basic colors to approximate the finer color ). Neither method results in a real smooth image, but one can generally get a good idea of what the image wanted to present.

2. For 256-color operation with any MS-Windows or MS-DOS software, a software "driver" (a piece of software which acts as a go-between between your operating system and your graphics hardware) must be installed. Often, this has already been installed an d activated by whoever sold you your computer. Occasionally, you must do this yourself. It is not enough that the hardware is capable of 256-colors, it must also have the software driver installed. Likewise, it is not enough that the graphics so ftware driver resides on your hard drive, it must be recognized by your operating environment. In MS-DOS, this probably means it is installed via a "device" command in your CONFIG.SYS file, or (rarely) invoked as a TSR from the AUTOEXEC.BAT file or comma nd line. In MS-Windows, it is installed from the "Windows Setup" utility. Consult your Windows documentation for procedures. Graphics software drivers are generally provided at no additional charge by the manufacturer of your graphics controller card, and occasionally by the manufacturer and/or retailer of your computer. Call them to obtain the latest version for your machine.

3. Assuming the hardware exists for 256-color (or better) operation, and further assuming the proper software drivers are installed, you should have no problem getting reasonable-looking pictures from Netscape Navigator. I notice that Netscape Navigator V1.1 (current as of June 95) dithers the colors to a pallete field somewhere between 16-colors and 256-colors (maybe 64?). This speeds up image processing under Netscape, and seems just fine for in-line images like buttons and icons, but leaves much to be desired for scanned photographic images. [Note: if you're already limited to a 16-color pallete, disregard the rest of this discussion]

I have found the use of external (i.e., "helper application") viewers to give much better results than Netscape's built in viewers. I use Leonardo Louriero's LView Pro for Windows 3.1, ver sion 1b, as an external viewer, and the images look great on my machine. LView will also allow gamma correction. The LView software is shareware, and free for leisure, non-busine ss use at home, and a mere $30 otherwise. In addition to the hyperlink highlighted above, the software can also be downloaded from well-known FTP software archive sites.

4. As an assist to novice users of Netscape who wish to install LView as a helper application for viewing images, I offer the following procedure:

assumption: LView has already been installed under Windows, per author's instructions
start Netscape
select the Options menu
select the Preferences submenu
from the "Set Preferences on:" box, select Helper Applications
scroll down to file type image/jpeg (extensions) .jpeg,.jpg,.jpe, and select it.
in the lower part of the larger dialog box, click the Launch Application bullet.
click the Browse button and locate the file lviewp1b.exe in your directory structure. Click on it to select it as your JPEG external viewer
from the "Set Preferences on:" box, Helper Applications, scroll down to file type image/gif (extensions) .gif, and select it.
in the lower part of the larger dialog box, click the Launch Application bullet.
click the Browse button and locate the file lviewp1b.exe in your directory structure. Click on it to select it as your GIF external viewer
Note: Netscape will continue to process "in-line" images, but now external images will automatically invoke LView.
select OK to close out the dialog box.

5. To apply gamma correction when using LView on external images, select LView's ReTouch menu, then Gamma Correction. Leave the RGB switch locked, and slide the gamma control to upward to provide a better display. For my 640 x 480 VGA dis play at home, no correction is necessary. For my 800 x 600 SVGA display at work, increasing the gamma correction to 21 or 28 (presumably corresponding to gamma correction of 2.1 or 2.8) corrects the dark picture nicely. When you finish viewing the pictu re, and go to close LView, the software will ask if you want to save the changes. Since LView is being used as an external viewer, and the photo is stored in a "temporary" file, answer "NO" to the query.

Unfortunately, LView apparently does not enable gamma correction automatically from the command invokation, so each photo must be manually gamma-corrected as it is called up. (If you know how to do it automatically, let me know how via e-mail below). Al so unfortunately, Netscape does not currently have the capability of automatically -- or manually -- performing gamma correction. Hopefully, this will be considered in future versions.

(done...return to photos page)


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