>> Home >> Magazine >> This page

>> 500+ other articles are available in our archive

 

Tech Tips

Finding a Perfect Match

With FS Color Server

n by Martin Waligiorski



Among the many sections of this site you will find a relatively new but prominent addition: FS Color Server. It is a colour search engine which allows you to look up any colours our of Federal Standard FS 595b range.

This article is intended to give some introduction to the intricacies of the FS 595b standard and its use, as well as provide readers with hints for how to use the Color Server's functions to their best advantage and how to interpret the results.

To start with, FS Color Server is available here:

FS Color Server

A Bit of History: The Pros and Cons of Federal Standard 595b

The Federal Standard colour system provide a means of comparing colours visually. It has its origin in the US Military complex and is still used there as prime source of colour reference.

More importantly, FS 595b is also old. Its origins reach back to World War II when a problem of providing exact colour specification to an equipment subcontractor on the other side of the World became manifested itself with obvious clarity.

The solution found then was to assign a reference number (or name if you look at the British system) to specific colour used, printing them on sample colour chips and then distributing the chips to the interested parties. This way any paint manufacturer or paint contractor could accurately mix a requested colour.

The limitations of this system are quite obvious. For the first, there can only be so many colour shades as have been envisioned by someone issuing the chips. In the case of FS 595b, there are 611 colours - not a great number by any measure. As a comparison, stepping into any paint store in Sweden you can obtain a fan of 1,750 colour chips as a reference for home decoration jobs!

Secondly, the chips in the FS 595b need to be distributed physically to all contractors, workshops and even individuals who work with mixing the actual paint. If they are not, there is no way of reproducing the correct colour, or even knowing how it approximately looked like, since colours with similar numbers can be significantly different.

Thirdly, the chips do not carry any information about how the original colour was composed - in other words the give no hint about mixing procedure. Up until the arrival of modern electronic colour-matching equipment, subcontractors had to mix correct shades using available pigments and visual matching, a task difficult  for just about anyone but experts in this area.

Last but not least, the Federal Standard 595b in not extensible, i.e. it does not allow to derive new colours form the existing ones. Thus, if you compare i.e. Japanese camouflage colours to FS codes, you can only refer to the nearest existing FS colour, which most often isn't a perfect match.

In modern time things look very differently. There is a number of colour systems, for example CMYK, NCS or RGB. These systems describe colours though their physical properties thereby rendering distribution of colour chips unnecessary and allow composing almost any number of shades within their colour space.

The widespread applications in the military is the reason for the stubborn prevalence of the FS 595b and consequently, its adoption for modelling purposes by scale modellers in the US. From there, FS 595b became adopted by the modelling industry worldwide despite the fact that non-US colours (such as British or German camouflage paints) can only be approximated to one or more nearest FS chips. You could say that the accuracy is good enough for most modelling purposes. But the requirement of having the FS fan deck in place to draw any advantage of the system remains its paramount flaw.

Here is where our online solution comes in.


Using the Server: The Basics

The basic function is simple. On the FS Server search form, enter a desired five-digit FS colour number and hit enter. The system will look up an appropriate colour and display a rectangular sample on-screen.

Samples can be enlarged for better viewing through an Larger Sample link at the bottom of the sample page.

Should you happen to enter a non-existing FS number, the system will return a message nnnnn is not a valid FS color number.

Trying to enter colour codes at random you will quickly notice that it is not at all easy to find a valid colour number at all! Therefore, the server will provide links which allows you to browse through the entire FS 595b set.

For Advanced Users: Composing Camouflage Schemes

What I personally think is the best feature of FS Color Server is its ability to combine multiple colours in a single sample. It allows you to compare shades directly on the screen side-by side. But there is another application which I find great for modelling: it allows you to set together a sample of an intended multicolour paint scheme to see how the colours look together on a surface.

All you need to do to get this functionality is to enter multiple FS numbers in the search form separated by spaces.

Here are a few examples:

RAF Dark Green, Dark Earth over Sky (34079 30118 34583)
RAF Dark Earth, Mid Stone over Azure Blue (30118 30266 35231)
US Olive Drab over Neutral Grey (34088 36173)
Swedish Air Force Dark Green over Blue Grey (34083 36329) 
 ...or even US Olive Drab - Neutral Grey compared to Swedish AF Dark Green - Blue Grey (34088 34083 36173 36329)

Looking for a perfect match for a paint job, one is frequently faced with a question if the result would look better if a colour is replaced by a slightly lighter/darker/more red etc. To facilitate this, the server will allow you to look up similar colours to the ones already presented in a given sample.

Example:

To find similar colours to brown 30080, click Similar colors at the bottom of this sample (30080).

For Advanced Users: Linking

Lastly, a link to each colour sample is permanent, so you can always use it to refer to a particular sample in an online  discussion forum or another web page.


Understanding the FS Colour Codes

The colours in the Federal Standard 595b set have no official names, just five-digit numbers.

3 5 2 3 1
sheen colour group code

The first figure can be 1,2 or 3 and indicates the level of sheen:

It is a curiosity that in the original 595b fan deck, some colour shades are represented twice or even three times - as gloss, semigloss and matt, while other occur only as matt or only as gloss. Why it is so remains a mystery, but it is an awkward reminder that the origin of each chip has been actual paint used somewhere for some purpose. In practice, this peculiarity makes the FS fan deck only difficult to browse.

In our colour server we have removed this deficiency, and any colour in the range can be requested either as 1-, 2-, or 3-. Of course, level of sheen cannot be reproduced on computer screen, so each of these searches will render the same result.

Example:

FS 35200 25200 15200

The second figure of FS code indicates a general colour classification group.

Unlike the original FS 595b, our server sorts these groups into organized colour palettes, which not only allows the user to get a good overview of available shades, but also makes it easier to look for similar colours to a given one to aid your visual matching - see above.

Example:

To browse by colour palette, follow the links in the list above.

The remaining three figures (third to fifth) combined into a number provide a general indication (but not definitive value) of the colour's intensity. Lower value indicates a darker colour, higher value - a lighter colour. The numbers have been assigned with gaps to allow addition of new colours.


How Accurate are These Samples?

Now that's the million dollar question, isn't it? Let me assure you that getting predictable and repeatable colour to your computer is not an easy task!

A fact of life known to many historians and modellers doing research on colours of their subjects is that every form of image reproduction - be it through photography, scanning, computer displays, printing and so on - has an issue of accurate (or not) colour reproduction. Go to any site devoted to digital still cameras and you will find just how much discussion there is about reds, greens, saturation, skin tones, white balance and so on. In our own modelling field, there are similar  perpetual discussions about quality of colour photographs in books, colour reproduction qualities of different films and so on.

What does it have to do with FS colour chips presented on your monitor? Quite simply, the colour you see has been affected by digital reproductions made to the original chip - and there are two of them. First, The the chip has been scanned by us to produce its digital rendition. Secondly, it is being displayed to you by your very own computer screen. This means that there were two occasions on which colours were transferred from one medium to another, with inevitable distortions - hopefully small, but far from insignificant!

Scanning

During the scanning process, we have tried to create as controllable conditions as possible with a limitation of having access to only standard scanning equipment. Without going into details, we have put a great deal of effort in ensuring that the scans are consistent and reflect the original colours.

Note that some special categories of colours do not scan well at all, namely metallic and fluorescent ones, as their reflective properties cannot be reproduced digitally. Silver scans to greyish shades, and fluorescent orange becomes  just orange in digital form.

Examples:

Chrome silver 37178
Fluorescent orange 38903

Colour Depth

Then there is an issue of how your monitor displays colour. First the basics. Be sure your display is configured for 24-bit or 32-bit colour. A display with 16-bit colour may not offer enough colour depth (meaning the ability to differentiate between similar but different shades of the same colour) to reflect sometimes subtle differences between chips in the FS Color Server database.

24-bit or higher colour capability is often referred to as Truecolor (giving 16.7 million colour shades). 16-bit colour colour setting is also called Highcolor. Giving 65 thousands distinct colour shades , this setting is considered sufficient for viewing colour photographs, but may impair the perception of images where minor differences in shade matter.

   Checking Your Display  

This test procedure applies to computers running Windows.

To check if your display adapter is configured for 24 or 32 bit colour you need to enter the Display Properties dialog box. Right-click on the Windows wallpaper (the background outside any open windows), then click on Properties, Settings.

Gamma correction

On an ideal monitor, black would be black, white would be white and picture-prefect Neutral Grey would be the 50% of white. In real life this is usually not true, an issue often referred to as gamma correction problem.

If a 50% grey is displayed darker than the 50% average between black and white, then the gamma is "low", if it is other way it is "high". A sad fact of life is that all Cathode ray tube (CRT) monitors for the PC have low gamma, meaning that for example Neutral Grey is in fact displayed significantly darker than it should be. If you are a Macintosh user, you haven't got the same problem - the Mac has built-in gamma correction which makes the colour luminance on the monitor appear as it should to the human eye.

Reverse the above statement and you will see that the same scanned image of Neutral Grey will appear lighter on a Mac than the very same image on the PC monitor!

How is it with modern plasma displays? You guessed it - different technology, different situation. The newest plasma displays often facilitate good to excellent colour reproduction, but many of the older ones did not have enough colour depth to be seriously considered a match for an analogue CRT display. Moreover, the gamma of a plasma display may differ depending on the viewing angle!

The noticeable consequence of bad gamma is that mid-tones appear distorted, usually too dark if you have a PC. Speaking in FS 595b terms, most of the camouflage tones will be affected this way.

   Checking Your Display  


The greyscale above presents multiple shades of grey from pure white to solid black. The pure white block at the far left should be as white as the background of this page, while the second block of very light grey should display just a bit darker than pure white. The solid black block at the far right should merge with the outline of the image, while the block just to the left should display a bit lighter than solid black.

Adjust contrast and brightness settings of your display to obtain satisfactory result. Most any monitor should have brightness and contrast controls, either adjustable wheels or buttons that allow up or down increments to be made.

Now to the actual gamma test. Step away from your screen and have a look at these three rectangles. From a distance,  pattern in the outline of each of the solid rectangles in the middle of each area should become indiscernible in tone from the patterned outline (it may help to squint your eyes a little). If it is so, the gamma of your display is set correctly. If the inner rectangles remain clearly visible, your display needs gamma correction.

Not all computers support adjusting a gamma curve, but if they do, it is usually done through the display settings dialog box or special software such as Adobe Gamma.

Colour temperature

It should be kind of obvious, but your monitor should be operated in subdued light; strong direct light should not reach the screen. Dark areas of the screen should appear dark to the eye.

Most CRT monitors have provisions for setting colour temperature. Colour temperature is comparable to white balance setting on a digital camera - it is your monitor's ability to reproduce whites and greys without a "background" colour tint.

The temperature is usually set directly on your monitor  using on-screen menus, and this is where adjustment can be made.  A good starting  temperature value is 6500K,

   Checking Your Display  

Pick a white sheet of paper and hold it against a large white area on your screen (like the background of this page). Is the "white" on your screen tinted pink or blue? If it is, you need to adjust the colour temperature of your screen.

For best quality, the test should be done in natural light, with well-diffused light from a window as the only light source. Artificial light has a colour tint in itself and will affect the perceived shade of the paper sheet.

As you can see, the devil is all in the details. But to most of us, given the inherent limitations of the Federal Standard FS 595b itself, the ultimate answer to the colour accuracy question is always: mix paints so they look good together on your model. In doing that, FS Color Server should provide you with good reliable guidance which  can be used with confidence.
 

n


This page: 
Has been last updated:
The URL of the page is:
Downloaded at:


©  Copyright 1997-2006 by IPMS Stockholm and the Community Members. All Rights Reserved.
The layout and graphics of this site, HTML and program code are © Copyright 1997-2006 Martin Waligorski. Used by permission.

Terms of use: This site is an interactive community of enthusiasts interested in the art of scale modelling of aircraft, armor, figures, spacecraft and similar subjetcs. All material within this site is protected under copyright, and may only be reproduced for personal use. You must  contact the Author(s) and/or Editor for permission to use any material on this site for any purpose other than private use.