Specifications for colour viewing station.

[nothernlights]

Does anyone know where I can find instructions on how to make a proper colour viewing station from scratch? I remember seeing the specifications in a book awhile back but I can't seem to find it or any references on the Internet. We are planning on either making one ourselves or purchasing a colour viewing station. Right now we are leaning on buying one but would still be interested in finding the instructions.

Thanks.

 

[meddington]

Re: Specifications for colour viewing station.

The ISO 3664 standard specifies the requirements that viewing conditions need to meet for the graphic arts, but I wouldn't exactly call it instructional...its really not a "how to". Making your own viewing station is possible, but confirming compliance to the standard can be tricky (or actually impossible with consumer level measurement devices).

 

[tmiller_iluvprinting]

Re: Specifications for colour viewing station.

Contact me offline and I will email you a pdf of the specs that I have.
Very best regards,
Todd

 

[michaelejahn]

Re: Specifications for colour viewing station.

@ nothernlights

Without a definition on what you are trying to accomplish, well, this can vary widely. Are we in the business where we are color correcting digital photography that needs to match fabric swatches, and we need to simulate a printing condition ? Even if you answer 'yes' this thread can quickly become a hotly debated thread !

Okay, so, as swatch matching would require that we all agree on the idea that you are needing a viewing booth that can accommodate a comparison between a physical proof and a monitor.

I will assume that you have already made your decisions about Adobe RGB 1998 vs sRGB, PDF/X-1a vs PDF/X-4 and exactly what Output internet and color policies you will use.

helpful hit - do this BEFORE you BEGIN to concern yourself with the design of the "Specifications for colour viewing station"

Okay, well, then I would start here;

[http://www.gtilite.com/gti-technote-archive.htm]

Even if you have a graphic arts supplier or color management expert whom you trust and are smitten with, you can never know enough about this.

And there is a LOT to know about this.

[http://picasaweb.google.ca/michaelejahn/20080326_SID]

If you have Skype we might talk (you spell color funny, <wink> so you must be in the opposite side of the pond) - mine is michaelejahn

 

[gordo]

Re: Specifications for colour viewing station.

Dear Michael,
Regarding your statement: "(you spell color funny, <wink> so you must be in the opposite side of the pond)"

While many newspaper weather maps present the U.S. as an island, there is in fact a little country at your northern border that also spells colour, among many other words, "funny."
;-)
best, gordo

 

[michaelejahn]

Re: Specifications for colour viewing station.

@ Gordo,

You were always good at pointing it out when I messed up - indeed, you are correct !

Color and Colour - anything but Kuler (Adobe Kuler, that is)

 

[Brenda Millard]

Re: Specifications for colour viewing station.

GTI is really the best option as they already meet the rquirements. They can also help you build a Custom booth should you desire one.

You can contact me if you have a model you are interested in - I would be glad to assist and can provide you additional discounts

Brenda
[email protected]

 

[eastppress]

Re: Specifications for colour viewing station.

Am I missing a lot or not? It seems that building a reflective viewing booth should not be that difficult other than the surrounding areas being neutral gray and having light sources of 5000k (I'd suggest having lights in the room of similar color temperature). The bulbs are expensive, but can be obtained wholesale over the web. To validate your work, you would need to rent, borrow or buy a color meter.

 

[meddington]

Re: Specifications for colour viewing station.

>Am I missing a lot or not? It seems that building a reflective viewing booth should not be that difficult other than the surrounding areas being neutral gray and having light sources of 5000k (I'd suggest having lights in the room of similar color temperature). The bulbs are expensive, but can be obtained wholesale over the web. To validate your work, you would need to rent, borrow or buy a color meter.

Depends on how far you want to take it. There's a lot more to the ISO 3664 standard that the color temperature. Chromaticity (aka color temp), luminance, metamerism index, color rendering index, uniformity, ect. Most instruments are not capable of measuring down into the UV spectrum to determine conformance. Manufacturers like GTI and Just Normlicht have high end spectroradiometers to confirm adherence to the standard (with Just having third party confirmation). Even with all this, there can still be visual differences between a GTI and a Just viewing booth. It may sound like going a bit overboard lighting can make a big difference, especially with the amounts of optical brighteners in papers.

 

[John W]

Re: Specifications for colour viewing station.

As I recal there are several issues:

1. Background must be Munsell N8 gray. This color paint csan be purchased from a Graphic Arts dealer and is very expensive but you'll likely only need 1 Gallon.
If you choose a paint store or box store paint, you may/will not be using the correct light absorbing/reflectance.

2. There is a certain number of lumen required per square foot of viewing area. If I remember, it takes two 2'x4' fixtures (ie 4 bulbs fixtures) side by each in portrait mode (24" left to right x 2 + 5 inches) with a gap between the fixtures of about 5 inches to cover a standard viewing area 66 inches wide. You should consider only bulbs that have a decent CRI (color rendering index)

3. These luminaires (fixtures) require a certain diffuser lens and must be at a tilt of about 20 degrees up from horizontal at the back. The table for placing items must be at the same angle, ie the luminaires and the table are parallel to each other. The table depth must not be deeper than the area covered by the light.

4. All walls surrounding the viewing area including the back wall must be Munsell N8 as must the ceiling and preferble the floor. This is for refelctance from the surround and also because the human brain can be fooled so easily if there is a brown wall for example nearby. The critical viewing time must be limited, usually no more than five minutes becasue the brain will alter ts perception to try and reach an equilibrium with the work. Go away and come back ten minutes later and spend another five minute maximum. I recall a boss who, if he faced more then a couple of red traffic lights on the way to work, would see all jobs as too red and make us etch and etch for nothing!

5. You must be able to turn off surrounding ambient light so place the viewing area inside its own room with a closable door. A huge consideration might be to include incandescent 60W light bulbs on a separate circuit for example if you are doing fashion catalog work and the homemaker will be viewing that dress she may buy from Sears in her livingroom by a 60W light bulb! Or the difference between say a Macbeth tube and a Durotest tube, 7 phosphors vs three! Personally, I dislike the Macbeth tubes as they appear very blue.

6. As a test, once you gitter done, try differecnt manufacturer's 5000K bulbs next to each other. You may be shocked to note that they are a rainbow of different colors!
Also that th output of the tubes will fade over time, so you should set a regimen of changing the tubes every year at the very least and change all the tubes at once.
I used to have every bulb in my shop as a 5000K Durotest brand and was delighted with the consistency and output lumen while finding the price in the middle of the three phosphor bulb range (Optima 50, 5000K or Vitalite, 5500K, CRI=91; natural daylight is about 5500K and CRI=100). I prefer the slightly colder light from Vitalite but now we're into persoanl taste not standards. Bulk buy enough bulbs for the year or two; it's way cheaper.

Hope this helps you

John W

 

[Buddy1017]

Re: Specifications for colour viewing station.

Ah, my specialty!
I wouldn't recommend building your own booth, because of all the concerns listed above.
In the interest of full disclosure, I work at GTI in the color lab.
To build your own booth you would need Munsell N8 equivalent gray paint (10-60% luminous reflectance means Munsell N4-8, but N8 is the overwhelming favorite). You'd also need a luminaire with ballasts, reflector, and lens that drive the lamps to a consistent and known output. To ensure this you need a spectroradiometer the yields 300-700 nm data (at least) in 5 nm increments (at least). At GTI we have 5 spectroradiometers that are all NIST traceable in their calibration. This is not something you want to buy. You’ll save a few pennies on the booth to spend over $8000 (one of ours would be over $30,000 to replace) on an instrument to ensure you are certified to ISO 3664:2000. Our lamp manufacturer also has a lab with spectros to check the CRI, CIE 51, color space (u’, v’, x, and y), correlated color temperature, and lux values (among other things) before we even see the lamps. They make the lamps exclusively for us and yes they are expensive.
Someone above mentioned 5000K lamps being all the colors of the rainbow. This can be true since 5000K is not a point in color space. It is a line where any lamp falling on that line can be called 5000K. The make-up of the lamp phosphors is really the thing that is important. The spectral power distribution graphs the energy output of the lamp at different wavelengths. It looks like a fingerprint and when you see enough of them, you know the lamp even if the graph isn’t labeled. Another thing caught my eye in an above post. The number of phosphors in a lamp is a great marketing tool, but not much else. I have worked with my lamp manufacturer to immitate other lamps and have been able to do it with less phosphors than they claim. I have even found two sets of lamps that plot exactly on each other, but have different spectral graphs. These two lamps look dramatically different to the eye. I won’t go into more of a commercial than I already have. I saw your question and immediately thought “penny-wise and pound-foolish”. Good luck in your quest for controlled lighting.

 

[jmeyers]

Re: Specifications for colour viewing station.

"1. Background must be Munsell N8 gray. This color paint csan be purchased from a Graphic Arts dealer and is very expensive but you'll likely only need 1 Gallon.
If you choose a paint store or box store paint, you may/will not be using the correct light absorbing/reflectance."

If you are interested in purchasing Munsell N8 Gray paint from a retail store, Sherwin Williams makes a product called Zircom 2129 that has the appropriate L*a*b* values for color viewing. (L*=81.35, a*=0, b*=0). Also, Graphic Technologies makes a Munsell N8 Gray specifically for this purpose.

Just so you are also aware, when you test your lighting source with a specroradiometer, your light should measure 2000 lux +or- 250. This is equivalent to 183 ft candles +or- 23. (Photographers typically measure in foot candles). Not to be salesy, but PIA/GATF makes an inexpensive product called the RHEM light indicator that visually shows you whether your light is 5000K or not using metamerism. Here is a link: http://www.gain.net/EWEB/DynamicPag...13-79541c167f16&prd_name=&ListSearchFor=7065R

If you have any questions feel free to call our technical hotline: 412-259-1786

Jessica Meyers
PIA/GATF
412-259-1791
www.qcproducts.org