Build Your Own Metal Halide (Low Cost “HMI”) Fresnel – Part IV

I got into this “Cool Lights” business of mine because I thought prices were outrageous on pro level fluorescent fixtures. You can see all over this site the manifestation of what I decided to do about it; starting with the Cool Lights video and ending with low cost fluorescent fixtures. Well, I’ve gotten the same feeling again on another lighting technology: HMI. I was searching for an energy efficient hard or point light source to complement our fluorescent Cool Lights Softlight Series product line and was learning about HMI as the natural solution. Crazy prices though and no good reason at this point to have them so high.

In the last part of this article series, we’ll take a look at the Cool Lights bulb choices for the various fixtures using Osram as the standard and then coming back and looking at other equivalents. You’ll see we chose to work with industry standards so you won’t be locked into using Cool Lights bulbs for sure.


When I was designing the new Cool Lights Hardlight Series fixtures, I considered using the elliptical type metal halide bulbs (E26 and E40 screw-in sockets) for a short time but rejected the idea very quickly because of their size and also because they just don’t yield the professional solution that a smaller pro type socket version gives. Are they great for a DIY solution? Yes, no problem there; that’s why I felt comfortable recommending it during the process where we built our own metal halide fresnel earlier in this article series. The issue is that the elliptical bulbs are are typically much bigger than their (G12, G22, GX9.5, etc.) counterparts especially in the larger wattages. Therefore, I chose to go the standard route followed by most stage and studio fixtures using the commonly available single ended socket types. This article will focus on the bulbs the Hardlight Series fixtures will use—mostly using Osram as the benchmark and then seeing what else is available.

The Osram Solutions

150 watts

For our Cool Lights fixtures let’s first look to the single ended Osram bulbs as our model and then see what else is compatible and available elsewhere. For simplicity we’ll consider only color temperatures in the 3000K/3500K and 5000K/6000K ranges and CRI of 80 or above. These bulbs are available in single ended and double ended but we will limit to single ended as those are best for Fresnel and Par type instruments. We also won’t consider the elliptical lamps with E26 or E40 bases as their sizes are too large for use in compact fixtures like the one’s we’re designing. For burning position, we like the universal type wherever possible. Why limit how the fixture can be used? That’s my feeling on this subject.

Cool Lights 150w metal halide Fresnel is using a G12 socket and our base line 575w par has a GX9.5 socket. A G22 in the 575w Fresnel and SportLight Par 575. The 1200w products, when they’re ready will use the G22 for non-hot restrike and G38 for hot restrike. So, the scope of this article is to cover the bulbs available in the socket types Cool Lights fixtures use. In general, metal halide bulbs fall into two technology families: quartz discharge tube and ceramic discharge tube. Quartz models are also known as “dysprosium” lamps and are the older technology. HMI type are all quartz.HQI 150w

Ceramic is mostly only available in lower wattages of 400w or less and also provides the possibility of the highest CRI’s too. For the 150w G12 base fixtures, there are the low end models of HCI-T and HQI-T ceramic and quartz respectively. Both available in 3000K and 4200K and CRI 90 for Ceramic and CRI 80 for quartz. The HCI come in a very standard 105mm length package but the HQI come in a shorter package of 84mm—the shortest of these type bulbs I’ve seen which means you could perhaps fit it in a smaller fixture. Since the center point or spot where the arc is at (“LCL” parameter) is the same distance as the HCI models, these bulbs can be used interchangeably. Unfortunately though you would be locked in to this bulb as I haven’t seen this package size from other manufacturers if you design a fixture that really needs its more compact length. The HCI-TM 250W/830 coming in G22 base, color 3000K and 4200K and CRI of 80 looks very interesting for a future 250w fixture offering.

Osram 150w HCDNext up the quality chain, there is the HCD and HSD “Architainment” types which are ceramic and quartz (respectively) metal halide bulbs also using G12 bases. The 4ArXS HCD 150W comes in 3000K and 4200K and CRI of 90. It has one of the highest lumen per watt ratings I’ve seen in these types of bulbs at 100—the average for most others is 85. Therefore, the lumen output is a big 15,500. The lifetime at 8000 hours although some GE and Phillips models have even longer lives. A high quality bulb and uses the very common G12 socket that we need for our 150w products. The 4ArXS HSD 150W/70 is the next closest color temperature but 7000K is really high and would require CTO filtering to bring it to more standard levels.

By the way, all the above-mentioned bulbs are non-hot restrike (too bad!). Even so, the 150w ceramic models are in many ways more interesting than the higher wattage quartz ones. Longer life, more lumens per watt and (perhaps the most exciting) the possibility of a high CRI tungsten color is a reality as is the more common daylight too. The older quartz metal halide bulbs are seemingly incapable of a high CRI tungsten color. When they try it, many times it comes out little better than a sodium vapor type and is totally unusable for photographic / video applications. I expect this to change though as the ceramic technology matures and is available in higher wattages. I’m not sure about Osram’s choice of 4200K for daylight other than to match existing 4200K common office type lighting choices. In the introduction, I said we wouldn’t consider anything outside of the 3000K or 5000K range but Osram doesn’t cover the high daylight range well in the lower wattage bulbs. Phillips and G.E. also made similar choices. The lack of solutions in the 5000K to 6000K range from the big manufacturers is inconvenient but not to worry, as other clone manufacturers fill this void with very interesting products which are lower cost also.

575 watts

HSD 575For the 575w bulbs, we have the HSD “Architainment” class which comes in a GX9.5 base; color temperature is 6000K and CRI is 85. The technology is quartz metal halide. Lifetime for the 575w is very long at 3000 hours; but then, all the HSD models have longer than average life specs. HSD has a protective outer glass jacket and has some other interesting single ended wattages for us to revisit in some future fixtures. For instance, the 250w and 1200w hold a lot of promise for another model of Fresnel and our 1200w par respectively.

HMI 575 HR Bulb



Next, the “Entertainment” class which come in HMI, HTI and HSR types. Most all of these are in 6000K color temperature with some variation on CRI between 85 and 90. HMI family are all hot restrike, all the other families for the 575w single ended are usually GX9.5 or GY9.5 base and non-hot restrike. The HMI 575W/SE and HMI 575W/SEL are of particular interest for our fixtures. These lamps both have a G22 base and are hot restrike capable. Specifications are nearly identical except that the SEL model has a 1000 hour life and 450 C seal temperature whereas the older SE model only has 750 hour life and 350 C seal temperature.

HTI family 575w are unsuitable for use in Cool Lights fixtures as we only use single ended bulbs and the 575w HTI are mostly double ended. Perhaps a future offering will use a double ended 575w though as they have their advantages in certain situations. While some of the other single ended wattages in the HTI line might be interesting, they are totally unusable for serious applications as the CRI values are very low. These models have no outer glass jacket, their life is somewhat shorter and they are optimized for projection or effect lighting. We’ll forget HTI altogether.

HSR is the bottom line, mostly for architectural lighting use but the 575w is completely usable for our non-hot restrike GX9.5 fixtures as the color temperature is 6000K and CRI is 85. Lifetime is 1000 hours. HMI and HSR families both have a protective outer glass jacket. Other models in this line such as the 400w or the 700w may be usable in a future fixture but the 1200w model seems unsuitable as it’s CRI is lower and is considered a projector or effect light.

HMI 200w SE HR BulbThere are so many base types for the different 575w models in these families. Where possible, we design for the 575w with a G22 base in the fixture so we can interchangeably use either hot restrike bulbs and ballasts or make the choice to use the less expensive non-hot restrike G22 base versions. If we design with the more common and compact GX9.5 or GY9.5 bases, we limit ourselves to non-hot restrike right away as the 9.5mm distance between the contacts means potential arcing during the restrike and is therefore unsuitable for hot restrike use. Only the less common GZY9.5 (as used in the 200w HMI model pictured right for example) and GZX9.5 (both with special ceramic insulation between the contacts), or the more common and larger G22 or G38 are hot-restrike-capable sockets.


The 1200w models come in either G38 socket for Hot Restrike Capable or G22 for non-Hot Restrike types. From Osram this would be the HMI 1200W/SE and SEL for Hot Restrike and the HSR 1200W/60 FS1 for non-Hot Restrike.


Now that we’ve covered the base Osram models, let’s look at equivalents. For the 150w, there are many clone ceramic and quartz metal halide bulbs out there in a wide range of color temperatures. Some far more interesting daylight colors than those offered by Osram for instance. We can certainly find some good 3000K colors too in relatively high CRIs so we can say the 150w world is covered very well for lots of choices. It’s one major reason I decided my base model was 150w—the bulbs are so easily found. The Phillips CDM150T6/830 3000K with CRI of 85 is well priced and also available in 4200K like the Osrams. The GE CM150/T/UVC/U is another choice. The Iwasaki Electric (which we’ve talked about before), Eye Color Arc 150w G12 offerings, are also very good with high CRI values and available in 3000K, 3500K, 4500K and 6500K. Ushio is another manufacturer to watch with their “Ceramique” series and 3000K/4200K choices and CRI is listed as “80 to 90.”

The Cool Lights G12 150w bulbs will be from a Chinese manufacturer and will be available in 3000K and 5400K. Our 150w fixture offerings will include one free bulb with choice of color temperature. Replacement bulbs should be in the $30 range. Lifetime will be about 2000 hours.

For 575w Hot Restrike, a good equivalent to the HMI 575W/SEL (with double the life at 2000 hours) it’s hard to beat the Phillips MSR 575 HR with color temperature of 6000K and CRI of 95. Another alternative a bit higher than the Phillips model is the GE HSR575/SE/HR with color temperature of 6000K and CRI of 90 and the GE CSR575/SE/HR with CRI of 95. Eiko has some of the best offerings in 5600K with the ESR575-SE-HR CRI 90.

For 575w non-Hot Restrike in GX9.5 base, many of the choices are disqualified (at least by me) for being CRI 75. We only have the MSR575/2 but it’s color temperature is 7200K and CRI is 80—not ideal. Ushio has some high wattage models like the 575w and 1200w, but CRI is not listed so it’s suspect and requires some more research. Eiko has the ESD575-SE-D and ESR575-SE-NHR in 5600K / CRI 90.

In G22 base non-Hot Restrike, the GE CID575 in 5500K and CRI of 85 is a great find. There are so many others too. When searching for equivalents, just use the model numbers given here and ask for a manufacturers equivalent to the Osram, Phillips or GE model you specify.




For 1200w Hot Restrike you have the G38 equivalent models from Phillips, GE, Eiko and others as well as the non-Hot Restrike G22 models.


As you can see, Cool Lights has made every effort to not only offer a lower cost solution but also a solution where you aren’t locked into some proprietary standard. We will offer reasonably priced clone bulbs as part of the fixture packages and also for replacements too, when it’s time for one. However, if you should decide, for whatever reason you would rather use an Osram, Phillips or GE as your replacement in the future, you can. All the bulbs we are using are available from a wide variety of sources and follow the standards for each particular family used.



Osram HCD 150:

Osram HSD 575:

Osram HMI 575WSEL:

Osram HMI 575W/SEL:

Osram HSR 575:

Osram HMI 1200W/SEL:

Osram HSD 1200:

Phillips Catalog:

GE Constant Color G12 bulbs:

GE Showbiz Catalog 2006:

Iwasaki G12 bulbs:

Ushio Catalog:

Ushio Ceramique Line:

Eiko Line:

(c) Copyright 2007 All rights reserved. May not be used in part or total without the express permission of the author in writing. Waiver of damages:This information and all included material are provided as is, and Cool Lights USA can not under any circumstances be made responsible for any damage, injury or losses caused directly or indirectly by implementation of the information in this article.


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