Loss of Detail

JPEG has a bad reputation by professionals who think that JPEG looses too much image quality. After testing this theory extensively, I decided that JPEG was an excellent choice for archiving images, as well as for film recording. These are some of the conclusions and rules I would follow.

• Do not use JPEG as a standard working format. Work in TIF or some other lossless format. When your work is finished, save a copy to JPEG for either archiving or imaging.
• Use high quality (low compression) JPEG settings. High compression settings are where the loss will show up.

Some interesting things we did notice about JPEG during the imaging tests:

• Despite being able to view some blocking up at high magnifications on the monitor, we were unable to detect them, even at enlargements up to 30x on photographic prints. Our conclusion is that "cross-talk" between dye layers in the film and the random grain pattern of the film help eliminate the effects of the JPEG compression.
• Despite the above statement, in areas where highly contrasting colors (i.e. black on white) formed sharp edges there was a slight softening effect.

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The Bottom Line

When viewing slides of the same image, and at the same resolution there will be no visible difference between the slide made from a jpeg file and the one made from a tiff, photoshop, or any other lossless format. For purposes of uploading and film recording, JPEG is an excellent format.

 

Photoshop PSD format through version CS3

The Photoshop default format is .PSD. We can image from this format if necessary, however some unexpected changes may occur to your image. For the best results, we would suggest that you save files you need imaged using the following Photoshop options:

1. Flatten the image. This puts everything on one layer with no floating objects.
2. Remove any Alpha chanels. The extra data in chanels will cause the image to behave badly when imaged.
3. Use the Mode option to make sure the image is in 8-bit RGB format.
4. If you have been working in another color space, convert the profile to either sRGB or Adobe RGB (1998).
5. Save a copy of the image in TIFF, TGA, or high quality JPEG format to send to us.

Following these steps before sending your files will both save us time and give you the results you expect the first time.

If you are having us image your files to negative film do not convert your files to negatives before sending them to us. When we open a file we have no way of knowing if this has been done, or if this is some special effect you are looking for. What you see on the screen is what prints will look like made from the negatives we produce.

 

Aspect Ratio:

Note that whatever the format of the original file you send we will not distort the image to fill the frame unless requested to do so. The standard 35mm film frame is 24 by 36mm (2:3). Images are enlarged from their original pixel size by equal amounts, Horizontal and Vertical, until one dimension reaches the edge of the film frame. Images are automatically rotated for the largest fit in the frame unless otherwise requested.

 

TIF files:

TIFF files come in many flavors. Fortunately we are able to read anything you send to us. There are however a couple of things you can do to make life easy and keep the files small.

• Make sure to save your TIF files in RGB color space. Color film consists of three dye layers: Cyan, Magenta, and Yellow. Exposures made on color film are exposed in three passes: Red, Green and Blue. CMYK files are designed for offset printing using 4 dyes to create a color image. It is good practice to use the appropriate color model for the desired output. As a bonus, RGB files will take less disk space than the CMYK counterparts.
• Save TIF files without masks or layers. This information will be lost in the imaging process, so save some disk space and file transfer time.
• Use compression. LZW, Pack-Bits, Strips or not, it doesn't matter. This will save disk space and transfer times.
• Use a maximum of 24 bit color. All the cameras image in 24-bit. 32, 36, and 48 bit files are reduced to optimum 24.

TGA files:

Some programs will not write compressed TGA files, but if you can use this option it will reduce file size quite a bit. We can read TGA in any flavor.

 

BMP files:

Windows BMP files are not compressed in any way. We suggest that you use a compression/archive program such as WinZIP to compress these files before sending them to us for imaging.

 

GIF files:

Be aware that while GIF files image very nicely, they are limited to 256 colors. Converting a GIF file to another format which has a higher number of colors will not increase the quality of the original file.

 

PNG files:

PNG format is no problem for us, but if you have many files to send, or they are large (in pixel size) you might want to consider JPEG as an alternative. Large files can take considerable time to encode and decode using the PNG format.

 

PICT files:

You can save PICT files from any Mac application and send them to us for imaging. We have no problem (so far) with any flavor of PICT file.

 

Sun Raster:

RAS files are one of the easier formats to image, these files can be compressed either with TAR or ZIP and sent in for imaging.

 

Amiga IFF:

As with RAS files, IFF are no different than any other raster format when it comes to film recording. Simply save your file to disk and send it in or E-Mail it to us. We have noticed that some IFF files are saved with a low Gamma, causing some shadow detail to be lost. When this occurs we will adjust the Gamma, usually to 1.25, to compensate. If you do not want any adjustment to be made, please let us know when you place the order.

The file formats listed here would not be our first choice for imaging. Each of these formats can cause problems of one sort or another. Despite the associated problems, if this is the only file type you have we can image from them. While many of the presentation programs will create many of these formats, we suggest that you upload the native format that your program saves, (such as PPT or CH3 or SHW etc.) or one of the PostScript or raster formats.

 

CGM files:

Computer Graphic Metafiles can be imaged, but because this format uses 'named' fonts there may be unexpected font changes during rasterization. Since CGM is no longer a common format we won't elaborate.

 

WMF files:

Windows MetaFiles are a very compact way to save many things created with presentation programs. These files usually image quite well, and some Service Bureaus actually prefer them. If your software is not on the supported list and will save to... or export... WMF files this would be a fairly safe format. Note that a WMF file is one page of your presentation, so you need to create one WMF file for each page of your presentation.

 

WPG files:

Word Perfect Graphic files are a Metafile format Specific to Word Perfect programs. Early versions are nearly identical to CGM files and can sometimes be viewed with a CGM viewer simply by changing the .WPG extension to .CGM. These files will image without any known problems.

 

DXF files:

Drawing eXchange Files are usually created by CAD programs. Our conversion process can cause named fonts to be substituted with another font. This can cause alignment and spacing problems. We can filter these files through one of our CAD programs (ACAD r13, or Designer) but exact conversion is not guaranteed. Imaging from AutoCAD is better achieved by the command PSOUT, or just send us the DWG file from AutoCAD in r13. or earlier.

 

PS files:

PostScript files are a page description language which in theory allows portability of files between platforms. Since the introduction of Level 2 PostScript this is not always the case. Most MAC's now ship with a Level 2 driver built in. This can sometimes cause problems if the interpreter is not Level 2 compliant. The most common problem is MAC presentation files with imported EPS Level 2 clipart embedded in the file. The clipart will convert to black on white, loosing any color information. We have at this time (we hope) eliminated this problem. I must admit that we have thought this was fixed several times in the past. If you must write PS files it would be advisable to keep them in Level 1 PostScript.

 

Writing PS files on a MAC:

To write a PostScript file on the MAC you need to have a PostScript printer set up on your machine. It is not necessary to actually have the printer. In Chooser, select printers, and add an Apple LaserWriter printer. When your presentation is complete, direct the output to the LaserWriter, and select the Write to File option in the dialog box. This will create a Postscript file on your disk which can be imaged by Gamma Tech.

 

EPS files:

Encapsulated PostScript files are a subset of PostScript. This is a page description language which defines how the page will be printed. The major problem with EPS is the wide variety of software that write their own versions of EPS. Saving an EPS file from one program and reading it in another is usually a problem. EPS written from popular programs like Freehand, Illustrator, PhotoShop and others will usually produce good results. EPS written from some programs, such as Corel Draw or Arc Info can create problems of various types.

 

PRN files:

Files with .PRN file extensions are usually either .EPS or .PS files. If this is the case we will have no problem with them. Some programs do not conform to this standard however, in which case we may or may not be able to image them.

 

When setting up slides for imaging there are only 2 things to do: Set the aspect ratio to 35mm slides, and save the fonts in the presentation. The aspect ratio is not critical unless you have things that must retain their shape in the final slide. Presentations set to other aspect ratios will be stretched to fill the frame of the slide. We typically load over 400 fonts, so forgetting to embed the fonts may also be a minimal problem unless you are using something radical.

 

 

 

 

 

Selecting the aspect ratio:

 

PowerPoint defaults to creating your presentation as a screen show, so if you need slides you should change the page setup to slide format. To do this in either 4.0, 7.0, or 8.0 first click on the File pull-down menu, and select Slide Setup... as shown here.

 

 

This brings up the setup window. Make sure that the setup says 35mm slides.

 

• If you change this setting after you created your presentation you will need to review your slides for possible shifting of text elements or resizing of graphics.

• You can leave your presentation in the default screen setting.   We will rescale the horizontal size when shooting to fill the frame. This will not move any objects within the image, and you will probably never see the difference. We actually stopped telling customers to resize their files over a year ago, and have yet to hear a complaint about the horizontal resizing when done in camera.

Saving fonts in the file:

When working with the Windows versions of PowerPoint you should include TrueType fonts in the file when you save it. This will avoid fonts being substituted when we open the file and insure that your slides look like you expect. To make sure your fonts are included, select either the Save, or if already saved, the Save As... selections from the File menu as shown below.

This brings up the Save dialog box. Make sure there is a check in the box as shown below.

PowerPoint 4.0 in lower left corner
PowerPoint 7.0 and 8.0 on right side of dialog box
Office 2000 hides the option in the tool menu
Office XP requires 2 steps, first select "Save options"
Then select these options

 

 

 

You may get a message about copyright restrictions not allowing fonts to be saved with the file. These are usually fonts that installed with a program, and with our base of default installations the font will most likely be on our system and not be a problem. If you are worried about it, write down the font name and we will make sure it is loaded.

Requirements:

PowerPoint saves a file with a .PPT extension. This is the file we need to image from. Normally no other files will be needed.

 

CLOSE

There are a few options to create slides from MS Word files.

 

Option #1

The page should look like a slide. To do this, first set the page size to the correct aspect ratio for 35mm slides. Select Page Setup from the File pull down Menu:

Next select the Page Size tab, and set the paper size to 8" by 12", in either Portrait or Landscape mode:

Next, Select the Margins tab, and enter .5" in all the margin settings:

After selecting "OK" you will get this warning:

Press "Ignore".

Now your page settings will be correct. If you want to have color backgrounds on your slides, you can follow the following procedure.

First, bring up the Drawing tools pallette, and select the Rectangle tool:

Drag a rectangle across the page and stretch it to fill the entire page. Next, right click inside the rectangle, and from the pop-up dialog box, select first "Format Drawing Object" which will allow you to set the fill color of the box.

Next, select the option that says "Send Behind Text".

You can now type in your text for the slide. Make sure font colors to contrast with the background. Use Large font sizes.. i.e. 90+ for the layout described above. Copy the Rectangle to additional pages if necessary.

When you have completed your presentation, you can E-mail the Word file to us for imaging.

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Option # 2

Lay out your presentation in outline format, and E-Mail us the file. We will convert your text file into 35mm slides.

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Summary

The primary difference in these three methods is price. All three methods are used on a routine basis by many of our customers using MS Word, and vary depending on their time constraints.

 

CLOSE

We get Excel files from some of our customers and they make great slides. You can create all types of charts, graphs and flow charts with Excel, and send us the Excel file for imaging. We would only like to point out one problem we see from time to time. Be careful how much data you put on a page for imaging. Too many fields in a single slide can force the font sizes so small that they are not readable.

It is best to print out your files before sending them to us for imaging. As a general rule, if they print out correctly on your printer they will image correctly on our end.

The Kodak Photo CD format is an excellent method of storing high quality images for a reasonable cost. Many times however there may be a need to have high quality digital output from these files. This is where Gamma Tech comes in.

 

The standard PCD format can be decoded into five resolutions. The highest resolution is 3072 by 2048. Our film recorders are set to image at a resolution higher than this, so nothing will be lost. For slides this is just another format, for negatives you have some choices to help you out with price.

Video capture has been made easy with several new products on the market, including the Play Inc., Snappy. We have done quite a bit of testing, both to slide film and to negatives, and find that JPEG files from the Snappy can make excellent images. As you can see on our Negatives Page, Imaging cost from these files can be as low as $2 each.

 

Since the usual need from video capture is negatives, we have not included a price break for slides from Video files, but... If you need a bunch of slides, call us for a quote and we will work with you on low-res imaging prices for slides.

The negatives and slides imaged by Gamma Tech lend themselves very well to CCD images from Astro Cameras. Depending on the CCD used, image sizes can range from 336x242 pixels upward. Post image processing can result in higher interpolated resolutions, but all resolutions fall below the imaging resolutions of our cameras.

 

What this means is that you can capture the perfect celestial object with your equipment, post process the image, then have photographic 35mm film shot by Gamma Tech, and surpass conventional film capability.

 

Negatives will make exceptional prints on a wide variety of printing materials, but you should be careful about enlargement sizes. Pushing things to the limit, the final print size should not be any less than 100ppi. (i.e. 336x242 pixel images should be kept to about 3.5 by 2.5 in size (wallet prints), while a 1536x1024 image will start to appear pixelated above about 11 by 14 inches.)

For printing we suggest a high gloss material, as it's outstanding contrast really makes astro images stand out.

 

File Formats:

While we are able to read almost any raster format image, we suggest that images submitted for imaging from CCD astrophotography be in 8, 16, or 24-bit TIF format, or SBIG format.

 

The most common question is: "Will my camera produce a good enough file for a slide?" The answer is: "YES"

 

Just about all digital cameras these days will provide files that make great slides. Anything above 2 MPixels will look better than it does on your monitor.

 

For best results, use the highest resolution, and capture the image in medium or high quality JPEG format. If you plan to edit the image in PhotoShop or some other image editing program, it would be best to capture the image in either RAW or TIF format. After editing the image save it in high quality JPEG format to send to us.

 

Most digital cameras capture images in a slightly different aspect ratio than a full frame slide. What this means is that when you have slides made from an unedited digital camera photo, the slide will have a small black border on the edges, like the one shown at the right. If you want the image to fill the full mount wihtout borders, crop the image in a 2:3 aspect ratio. (2:3 is the same ratio as a 4x6 inch print.)

 

What about color balance? Our process is balanced to produce the most accurate color possible on transparency film. Film can produce a much wider range of colors than a computer monitor, so comparing the slide to a monitor is difficult. Here's a very simple way to judge your monitor color, density and contrast without spending hundreds or thousands of dollars on software and calibration devices. The scale below is a 16-step gray scale. First of all, it should look gray. You should also be able to see differences in the steps indicated. Steps 15 and 16 are difficult to see on any monitor, but you should at least see a difference from 14 to 15, and some LCD monitors may have trouble with the brighter steps. If this scale looks good on your monitor, and your files look good on your monitor, then you will be very pleased with your slides.

You might wonder why we list fractals separately since they are usually GIF format. We have been imaging fractals for a long time, and have realized that there is more to a good fractal image than just sending it out to a film recorder.

 

Film recorders image files at a specific resolution. Fractal images are usually created for screen display resolution, or a multiple of those resolutions. Unfortunately these two systems do not mesh correctly, which can cause extra lines to be added (or dropped) when the file is imaged. The result is that the slide or print will not accurately represent the fractal image.

 

Gamma Tech overcomes these problems by imaging fractals at exact multiples of the fractal resolution resulting in accurate images. We calculate these magnifications such that the image will have a black border all around the fractal, (nothing will be cut off by either the slide mount or by a machine printer).

 

Here are some of the most common sizes & magnifications for fractal images.

 

Fractal resolution	magnification factor	Film Resolution
640 x 480	5	3200 x 2400
800 x 600	4	3200 x 2400
1024 x 768	7	7168 x 5376
1280 x 1024	5	6400 x 5120
1600 x 1200	2	3200 x 2400

 

Please be aware that film recorder resolution does not increase the resolution of the original file. Notice that the 800 x 600 file above would be magnified 4 times, and the 1600 x 1200 file would be enlarged only 2 times making the final film resolution equal (3200 x 2400 pixels). When viewed side by side, the slide made from the 800 by 600 file will appear only 1/2 the resolution of the 1600 x 1200 file despite being magnified 2x as much.

 

Given all these factors, our recommendation is to create low resolution images for screen display, when you select fractals for imaging, render them at the 1600 by 1200 resolution for imaging.