Luminous Landscape Forum
Raw & Post Processing, Printing => Printing: Printers, Papers and Inks => Topic started by: Light Seeker on August 16, 2011, 01:12:36 pm
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I am planning to display canvas prints, and a few black and white images, under a set of Solux MR-16 track lights. I would appreciate some input on the lighting configuration.
I have a set of 7' high black panels coming. Each panel is 2.5' wide. The layout will be 3 panels across the back (7.5') and 2 panels on each side (5'), arranged in a "U". The track lighting will sit ~1' above and ~2' away from the panels. Print sizes will typically be 14"x22" or 20"x30". I will display prints using the top ~5' of the panel (i.e. the bottom 2' or 3' will not be used).
I am planning to use 50w, 36 degree, 3500K Solux Black Back lamps. I am thinking that a single lamp will cast enough light to cover a panel, which means I'll need 7 total.
Will this do the job?
Thanks.
Terry.
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Horizontally that sounds about right but you're going to have a lot of fall off from top to bottom. Your light is about 1 3/4 foot from the top and 5-6 feet from the bottom of the area you want to light. I would say this set up is more suited for prints within 2 feet or so of the top (or wherever the light is aimed). Can you get the lights further back from the panels?
Rob P
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That's a good point.
The fixtures holding the track will sit at about 8' high (12" to 15" above the panel). They can be positioned between 25" and 42" away from the panel where the print is.
(http://www.propanels.com/img/lightbar.jpg)
So, at the extreme end I will have 3.5' of separation, light to panel, which will of course increase the spread of light. Will that be enough to provide proper vertical coverage? If so, will one light per panel still be enough?
Thanks.
Terry.
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I hate trying to order lighting for a show :'( as I find it tough to figure this too without having actual lights to fiddle with.
The 42" offset sounds better for vertical coverage. Now if I remember my trigonometry, 36 degrees at 42" corresponds to 27" (42 tan 18 times 2). If the lights don't have a lot of overflow past that region (and I must admit to not being familiar with this specific light, I'm just going on your specs and my personal experience show lighting) I still think you're still likely to have trouble at the bottom.
Ultimately will depend on how you lay it out. If you've say got one row of either one 20 x 30 in portrait or two 14 x 22 in landscape, you'll be fine and it'll look great. If you need to stack up the 14 x 22s 4 high, I'm worried the lower ones will be significantly darker. If you have a few more lights and alternate them up and down it might work.
Good luck. Where's your show?
Rob P
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Your trig is correct, and I'm really glad you brought this up. Assuming the lights are bright enough at this distance, they should cover the majority of a panel's width. Height may be an issue however as you've noted, so I will take that into consideration when I mock up my display in Photoshop. I'll use that to finalize my configuration & order. The event is 5 weeks out so I should have enough time to test and adjust if necessary.
These are the lights I'm looking at . . .
https://www.solux.net/cgi-bin/tlistore/colorproofkit.html
I'm on the Canadian Prairies. I have an opportunity to display images at a week long conference my church is hosting. It's a regional event and we'll have ~350 attending. Some of my work is tailored to this setting and some is more general. I set up a smaller display a few months ago at the same type of event about 1/3 the size, run over a weekend. I did reasonably well. It's a relatively safe environment to learn the ropes before trying the arts and crafts shows.
I appreciate your help.
Terry.
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Well, I had decided to order two-50w lights for each 2.5' panel, one to cover the top 1/2 and one the bottom 1/2. That should have covered about 5' of my 7' panel (vertically), nicely doing the job. However. . .
I just discovered that Solux makes a plano-convex diffuser. This doubles the beam spread and softens the light. With one of these clipped on the front I should be able to cover two panels wide (5') by 5' feet high. The light output will of course be less (1/4), but I'm wondering if I can get away with two-50w bulbs to cover this area.
Any thoughts / comments about his approach?
Terry.
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I'd say it comes down to whether you think your work looks better under diffuse light, or under collimated lighting. Also, if you're displaying at a show, having a lot of light on your prints will make them stand out better.
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Seeker, just curious why you opted for the 3500K lights as opposed to 4700K, no opinion here, just curious.
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Not trying to speak for Terry here, but I've tried all 3 (35/41/47) and I was surprised how cool the 4700's seemed. We use the 4100's in our color correction station, but the 3500's do not look exceptionally warm and I've used those to light some display prints which look terrific - just seems to make the prints pop a little more.
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Terry, I was interested in your post because I addressed the same types of questions when lighting my dining room (planning to have prints on the walls) and my computer/printing photography work area. You should look carefully at a photometrics chart. I'm looking at a 2006-2007 one from Lightolier, titled "Accent Lighting Performance Data" at the back of their "Lighting Handbook," a thick catalog for which I'm sure there is a current version. Your original estimate of one 50-watt approx. 40 degree spread MR-16 bulb per panel sounded right to me. Looking at the chart and applying your numbers, with one bulb per panel, your bulb would be 2 feet out from the panel and 3.5 feet from the center of the portion you want to light. That gives you only 63 foot candles at the center of your beam. You should figure out what an appropriate level of foot-candle illumination is for the type of display you have in mind. Interestingly, with the angle of the beam (about 30 degrees; it is measured as compared with a straight vertical drop), the chart indicates you would get a 2.9 foot spread horizontal beam 3.5 feet from the bulb, and a 9.7 foot vertical spread. Bear in mind that the beam spread measures the point at which the foot candles are only half of what they are at the center of the beam. To get the same illumination at the edges as you have at the center, you need another bulb the same distance from the original one as the beam spread. That is, if your beam spread is 2.9 feet, you need the bulbs to be 2.9 feet apart to get even illumination, and you need an extra one on each end if you're concerned about the outside areas of your display. This stuff is complicated. BTW, I would endorse your use of 3500 Kelvin bulbs. They're closer to the light temperatures people have in their homes. Even my PAR 30 halogens in recessed lighting are warmer than that. The MR-16 bulbs certainly look contemporary, but compared to bulbs with a broader light source, you end up needing more of them. BTW, I add diffusers to mine to cut down on the glare, and provide a protective shield should anything shatter., as they can do. If you want to talk with another company about the photometrics information, I would call Bulbrite. Online they are www.bulbrite.com. It does seem that with the lighting angle you are planning, your issue is really the horizontal beam spread and footcandles that yields, rather than the vertical spread. Good luck. Let us know how it turns out.
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About 10 years ago I met with Solux and tested the three different Kelvin Temps to determine which was best for the Epson booth at major trade shows.
4100K worked and continues to work the best for us in a trade show environment.
If you are using Solux branded fixtures all will be well, but I learned the hard way that some transformers on some fixtures reduce current which will lower the effect Kelvin Temp of the bulb.
Dan (Dano) Steinhardt
Marketing Manager, Professional Imaging
Epson America, Inc.
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Well, here's another note on photometrics. I do think you need to be careful about spacing and footcandles (light level). Above my working desk, I have three MR-16 bulbs, which I am rather sure are 50-watt and approx. 40-degree spread. They are 30" apart and 4ft3in. straight above the desk (zero angle for photometrics). Also, I have both diffusers and eggcrate baffles over the bulbs. I decided on the spacing after consultation by phone with the people at Tech Lighting (whom you may want to call), and get rather even illumination on the desk. The chart at the back of their (several years old) catalog, indicates that with that configuration I should be getting a little less than 125 footcandles. The desk is nicely lit, and certainly not overlit. I would suggest you figure out what ballpark you should be in on lighting level, and check out the charts for the distances (and angle) you are considering.
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At 4000K the ideal light level at the print could be 40 fc - 430 lux if the Kruithof curve is considered. It is not that strict though but probably the right guide to use. I have several 36ยบ angle, 50Watt, 4500K halogens, GU 5.3, from another manufacturer that actually measure 4000K (+ a nice spectral plot) with the transformer I use (have to measure its voltage but the capacity is high enough). I intend to use 4 diffused lamps as viewing lights for an approximately 3'x4' magnetic whiteboard.
met vriendelijke groeten, Ernst
New: Spectral plots of +250 inkjet papers:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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Seeker, just curious why you opted for the 3500K lights as opposed to 4700K, no opinion here, just curious.
Wayne and others have mentioned most of the reasons I'm looking at 3500K. Their feedback around this has in fact been very encouraging (thanks!). All that I would add is that I understand that UV and IR are better suppressed with the Solux 3500K bulb. 4100K is good as well, but I believe that 4700K and 5000K are not as well behaved in this regard.
Barbara, I will work through your suggestions. It's nice to know where next to turn for the science & math behind this.
Ernst, I had wondered what light level I should target. I was using my light meter last night to try a get a sense for this, but it won't display a lux equivalent.
Terry.
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Ernst, I had wondered what light level I should target. I was using my light meter last night to try a get a sense for this, but it won't display a lux equivalent.
Terry.
Check a Kruithof curve diagram and you will get enough information on the light level variation possible for the Kelvin grade you want to use. In FC and Lux. As you do not have to correlate that with a monitor light level it will be easier. My old Lunasix 3 has the Lux, FC tables at the back but I trust the colorimeter better. You should also check the actual Kelvin grade in your set up (transformer!) if possible, I did get a different Kelvin grade from Gretag's Share than from ArgyllCMS Illumiread with an i1 Pro but the spectral plots were similar. A good article on display lighting is here:
http://cool.conservation-us.org/waac/wn/wn21/wn21-3/wn21-308.html
It confirms more or less the experiences in this thread.
met vriendelijke groeten, Ernst
New: Spectral plots of +250 inkjet papers:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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Ernst, I have for a long time appreciated your posts on this forum, and have only recently become a participant when I thought I could offer something. Thanks especially for the link to the Kruithof curve and the accompanying article. Fascinating!! The relationship between light level and light color (temperature) was particularly "illuminating." Interesting that as one uses a dimmer to reduce light level, the effect is also to reduce the color temperature, just the effect you'd want to orchestrate if it didn't do it automatically.
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If I buy more Solux bulbs they will be 4100 deg. I have 4700 now and they are a little too cool. 3500 I would be afraid is too warm.
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Interesting that as one uses a dimmer to reduce light level, the effect is also to reduce the color temperature, just the effect you'd want to orchestrate if it didn't do it automatically.
Be careful with that method, the relation between the Kruithof curve and dimming may not be 1:1 and halogens need a certain temperature to keep their lifetime, the halogen cycle is not effective if the temperature in the lamp is changed too much from the original specification.
met vriendelijke groeten, Ernst
Dinkla Gallery Canvas Wrap Actions for Photoshop
http://www.pigment-print.com/dinklacanvaswraps/index.html
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Here is a link to a post by John Paul Capongro, who recommends the 3500k bulbs:
http://www.johnpaulcaponigro.com/blog/5095/review-solux-lighting/
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Just wanted to chime in here about the 3500k solux lights, we use them in our gallery and can't say enough about how well they work on photography and art.
http://www.redbubble.com/people/pemay
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Above my working desk, I have three MR-16 bulbs, which I am rather sure are 50-watt and approx. 40-degree spread. They are 30" apart and 4ft3in. straight above the desk (zero angle for photometrics). Also, I have both diffusers and eggcrate baffles over the bulbs. I decided on the spacing after consultation by phone with the people at Tech Lighting (whom you may want to call), and get rather even illumination on the desk. The chart at the back of their (several years old) catalog, indicates that with that configuration I should be getting a little less than 125 footcandles. The desk is nicely lit, and certainly not overlit.
Barbara. . . this sounds very similar to my situation in many respects, and what I'm looking at doing. Solux makes a Plano Plano diffuser and the rep told me to assume loosing ~1/2 of the light with it. He also cautioned that the published bulb specs were ideal, and when I suggested assuming 80% would be realized he agreed. If I map those two parameters onto your situation it suggests you might be getting ~50fc at your desk. That seems to align with your comment that the desk is "nicely lite, and certainly not overlit".
Terry.
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Terry, interesting point about the diffusers. Also, I have a dimmer on the set-up at the wall switch, so don't have to leave it at full output. As I think about the kind of lighting calculations you're doing, I would say to bear in mind that as you get to the edge of the beam spread for any bulb, you've already lost half the light. If you want even illumination, you need to have your overlap at that point, or near it. And you can be surprised how many of these little lights you need to cover an area. Please tell us how your lighting plan works out.
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I have learned a great deal from this thread, and through the subsequent research I've done. Thanks to everyone for your thoughts, suggestions and recommended reading. This has been fascinating!
I am planning to order track lighting with one Solux 3500K, 50W, 36 degree MR 16 bulb for each 2.5' section of my display. I would like to light approximately 5' of the 7' panel vertically, with the top 1/2 or so being the most important. The booth is 7.5' wide by 5' deep.
My light bar sits 15" above the top of the booth and I plan to set it so the track lighting is 36" away. If I shine the bulb at a point 21" down from the top of the panel (36" vertically down from the track lighting) the light will be 51" away from the print, and it will be shining at a 45 degree angle. When I look at a generic photometrics chart, take into account differences from the Solux bulb, and factor in bulb/transformer inefficiencies, I get a light level of ~70fc and a beam spread of ~2.7' across by ~4.4' vertically. If I diffuse the bulb the light level goes down to ~35fc.
The purpose of the booth, at least for this event, is to sell artwork. The space I will be in is lit by florescent tubes and I will have no control over ambient light levels.
Will 70fc be enough? It still (easily) falls into the acceptable range identified by the Kruithof curve for 3500K lighting. While diffused light might be nice, I don't think that 35fc will be bright enough.
Any last comments or suggestions before I pull the trigger?
It will of course be interesting to see how this actually works out in real life. My concern now is to prove out my basic approach, and to make sure I'm in the ballpark before I move forward.
Thanks all.
Terry.
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I've been using their 3500K bulbs in our gallery and amy very pleased. Solux has a "white paper" on why that temperature is the best for viewing prints and I agree. The higher temp bulbs just look blue. I don't feel the 3500K light is too warm at all. It's "just right."
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Will 70fc be enough? It still (easily) falls into the acceptable range identified by the Kruithof curve for 3500K lighting. While diffused light might be nice, I don't think that 35fc will be bright enough.
Terry.
Wilhelm calls 450 Lux (40 FC approx) a standard (average) display condition. For fade prone art the local museum here uses 50 Lux (4.4 FC approx) at 3000K. Aardenburg Imaging mentions several standards but for color evaluation a value between 500 and 2000 Lux (D50 illumination, so cooler) is required. 70 FC (800 Lux approx) should be fine for 3500K.
met vriendelijke groeten, Ernst
New: Spectral plots of +250 inkjet papers:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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Terry, you may need to talk with a lighting designer to give you a good reliable answer to your question. But let me give you a comparison that makes me think your planned lighting should work. I have a 35-watt MR-16 (not Solux) 3ft9in above and 3ft9in out from a print that is 31in. square and that is sufficient to give it a nice soft lighting. Your 50-watt will provide that much more light, and from a closer distance. If you do a Google or Bing search for "recommended footcandles" you will see some interesting examples of recommended light levels. Try this site: http://www.mts.net/~william5/library/illum.htm#6.) where you will also see the paragraph on "When to Break the Rules", which says that "for applications involving merchandising, advertising, decorative, artistic applications...it may be necessary to provide..higher than recommended lighting levels to achieve proper impact." I think you will want your lighting to be at a higher level than the overall surrounding lighting, so that is another element.
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Forgot to mention, my 35-watt bulb also has a diffuser and an eggcrate louver over it, further reducing the light. I do think a 50-watt for each of your panels should be fine. If in addition to that (reducing the light), you want to consider adding a diffuser, make sure the fixture into which you are mounting the bulb can take it (that is, make sure it has the capacity for a filter).
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Order placed. I will put ArgyllCMS onto my laptop, measure the light levels I actually get when I set this up, and report back. It will be interesting to see how close theory and reality align.
Ernst, thank you for your perspective on light levels. That was reassuring.
Barbara, your real-life example was very helpful and also reassuring. I did order diffusers so I have choices. The fixtures have what's required to mount then. Should the diffusers lower the booth lighting too much I'll eventually use them when lighting my studio.
I also ordered two 5000K bulbs for colour proofing and for comparison, along with some 3500K PAR bulbs to try out.
If anyone is interested, here is a link to the Color Proofing Kit I've ordered. . . . .
https://www.solux.net/cgi-bin/tlistore/colorproofkit.html
Terry.
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For confirmation, there are many low cost Lux meters on the market today. For example, go to http://www.amazon.com/ and enter "lux meter" in the search field. There are some lux meters at astoundingly low prices (less than $30). While the low cost meters may not be super accurate (my research grade lux meter cost over $2000), they should be close enough to help you confirm that your lighting method is producing a reasonable level of illumination at the print surface.
As Ernst noted, critical color evaluation takes a minimum of about 500 lux at the print surface, although many museums will light fragile works of art as low as 50 lux. For middle-aged and senior-aged eyes, 50 lux is a serious challenge in terms of experiencing decent color fidelity in the art work, but at 500-2000 lux, you get where you need to go in terms of high quality gallery lighting.
Another thing you will learn with a lux meter is just how tricky it is to evenly illuminate a large piece corner to center to corner. Some people, however, will conclude that a little fall off (e.g, one "stop" or about 50% of the max center illumination level) in the corners actually helps to draw you into the main subject matter of the artwork.
cheers,
Mark
http://www.aardenburg-imaging.com
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For confirmation, there are many low cost Lux meters on the market today. For example, go to http://www.amazon.com/ and enter "lux meter" in the search field. There are some lux meters at astoundingly low prices (less than $30).
I have a Sekonic flash meter (L-358) that I tried the other night but I didn't spend much time to work out what it can do in terms of measuring ambient light. It turns out that with one dip switch change it will display EV values. The manual has a table to convert EV to Lux so if I get that into my iPhone I can measure light levels anywhere. I can retract the ambient dome and use it measure flat surface light levels and also light fall off. It will take two ambient readings and show me the delta between them.
I am looking forward to working with the lights and building my understanding about lighting artwork.
Thanks Mark.
Terry.
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How does one measures illuminance and color temperature with an Eye-One Pro? i1Profiler doesn't seem to provide that information.
I've just started experimenting with Argyll's spotread with the following flags:
spotread -v -S -a -T -H
This is giving me a Lux and a CCT reading. How reliable are those readings? Am I on the right track?
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How does one measures illuminance and color temperature with an Eye-One Pro? i1Profiler doesn't seem to provide that information.
I've just started experimenting with Argyll's spotread with the following flags:
spotread -v -S -a -T -H
This is giving me a Lux and a CCT reading. How reliable are those readings? Am I on the right track?
Gretag Macbeth's i1Share
ArgyllCMS Illumread
met vriendelijke groeten, Ernst
New: Spectral plots of +250 inkjet papers:
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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Gretag Macbeth's i1Share
ArgyllCMS Illumread
Thanks Ernst! i1Share (http://www.xrite.com/product_overview.aspx?Action=support&ID=765) did the trick.
I couldn't get illumread to give me an illuminance reading. All I can see is to use specplot with illumread, but that only gives me the CCT, no Lux.
spotread -a gives a Lux reading but the documentation seems to indicate '-a' works only with an Eye-One Display 2.
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spotread -a gives a Lux reading but the documentation seems to indicate '-a' works only with an Eye-One Display 2.
I've been using spotread -v -a to measure light levels using my Colormunki. I compared those results with readings from my Sekonic flash meter and allowing for a reasonable margin of error, they are the same.
Terry.
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I've been using spotread -v -a to measure light levels using my Colormunki. I compared those results with readings from my Sekonic flash meter and allowing for a reasonable margin of error, they are the same.
Excellent! I also compared i1share to spotread -a and the results are identical using an i1pro.
One more question, the sensor should be oriented square with the artwork, not toward the light source, correct?
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My lights arrived and I wanted to report on how things worked out.
I set up a corner section of my booth and hung 3 canvas prints. A 20"x24" print was hung 2" from the top. A 20"x28" print was hung 20" from the bottom and a 14"x20" print was positioned in between these two. They were all in landscape orientation, and the three prints comfortably filled most of the 2.5'x7' section. More specifically, I had planned to use ~5' of the vertical, and that is how I positioned the prints.
I took measurements on all four sides of each print (midway on the side) and in the centre. The ambient light level in the room was 184 lux. The brightest point was the bottom of the top print without diffusion and the center of the top print with diffusion. It measured 905 lux without diffusion and 520 with diffusion. I had estimated that I would get 753 lux (70 fc) without diffusion and 377 lux (35 fc) with diffusion. I've done better, and the difference seems to be the 20% reduction I applied to account for inefficiencies. That factor was not required, and removing it virtually brings the numbers into alignment (theoretical versus measured). That's cool.
Shifting to light coverage now. Without diffusion the light levels across the top print varied by 1.6 EV. The second print varied by 0.7 EV and third by 1.1 EV. Note that the second print was smaller and yes, I realize it would have been more balanced to have used sample points spread evenly across the panel. However, I wanted to test a real-world scenario.
With diffusion the light levels across the top print varied by 0.6 EV. The second print varied by 0.8 EV. The third print varied by 0.8 EV.
I much preferred the diffused lighting. It was more even and more pleasant to look at. Giving up some light level was well worth it. In fact, the prints looked "just right". Not too bright and not too dark, almost as if they weren't even lit. You could of course see the difference when switching the lights off and on, and the kind of "pop" they added. Conversely, with no diffusion you knew they were lit, as the light was harsher and you could see the brighter area where the bulb was aimed.
I did one last experiment. I turned off the overhead florescent lights to see how the prints would look when the ambient light was significantly reduced. This was a boardroom with windows on one side, and it became noticeably dim but not dark. Unfortunately I didn't think to measure the ambient light. In this light the prints looked somewhat under-lit. This is of course subjective, and without the a-b comparison, and with some time for my eyes to adjust, I might have formed a different opinion. The room was likely close to subdued museum lighting. However, I want the prints to have an impact (i.e. marketing) and the first environment I will be in has an ambient light level of only 50 lux. So, I will be adding some fixtures to increase the overall level. The way my light bars are positioned allows me to mount fixtures further away to get the wider coverage I need for this.
I am very pleased with how things turned out. The methodology used to integrate two sets of data, and the general math behind all of this, worked well. Most importantly, the prints look great under these lights.
Thank you again to everyone who helped me work through this. I hope this information is useful to someone else down the road.
Terry.
<snip>
I am planning to order track lighting with one Solux 3500K, 50W, 36 degree MR 16 bulb for each 2.5' section of my display. I would like to light approximately 5' of the 7' panel vertically, with the top 1/2 or so being the most important. The booth is 7.5' wide by 5' deep.
My light bar sits 15" above the top of the booth and I plan to set it so the track lighting is 36" away. If I shine the bulb at a point 21" down from the top of the panel (36" vertically down from the track lighting) the light will be 51" away from the print, and it will be shining at a 45 degree angle. When I look at a generic photometrics chart, take into account differences from the Solux bulb, and factor in bulb/transformer inefficiencies, I get a light level of ~70fc and a beam spread of ~2.7' across by ~4.4' vertically. If I diffuse the bulb the light level goes down to ~35fc.
<snip>
It will of course be interesting to see how this actually works out in real life. My concern now is to prove out my basic approach, and to make sure I'm in the ballpark before I move forward.
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Great!