I would be in need of a little help regarding MH colour. As important as the colour rendering, the lamp appearance should be considered as well.

Most of you know about my MH table lamp that takes a protected ED lamp of 50 watts. I have also tried (no time for pictures at the moment, but will be coming soon I hope) a 35W one as well. The problem exists with the 50W but more so with the 35W. While the colour rendering is very good, the appearance leaves to be desired. The shade on the 50W is cream coloured while the 35W has a pure white shade.

Here is the problem (mainly with the 35W one with pure white shade) : I am looking at using a 3000K lamp to make the eye think it is an incandescent (or halogen) light source, but the appearance is way too much pink for that. I am thinking the pure white shade is treated with some kind of fluorescent dye to make it whiter, and the light from a MH source excites it to the point of being pink. Not pinkish, but pink. I have resolved to use a 4000K lamp for now, but I would like to return to the 3000K. Am I aiming for too high of a goal ? The 3000K lamp I have is a Philips Mastercolour 830 with a cylindrical arc tube, made in Belgium (I think but definitely not China). Changing to a cream shade would help but not eliminate this phenomenon.

To better define what shade of pink I'm experiencing, it is close (but not equal) to the pink of a flashing MH lamp during warmup.

I know member Lantern_Vision has some Osram Powerball HCI in 930 that appear to give a good appearance, however I have only seen them in pictures and cameras are notorious for changing the colours a bit (or a lot, depending).

I have been in stores lit with 3000K metal halide lamps that I thought were incandescent at first. One such example, I had to wait a couple of years to see some close to EOL and were either greened out or pinked out, proving they weren't incandescent.

I thought about rethinking my whole design to eliminate the translucent shade and eliminate that part of the problem but this is to be used in an office type environment and will make plain photocopy paper appear too pink. I know, I'm fussy and I'm asking for the moon...

While I haven't seen your light, will a Par30 lamp fit, I'm a huge fan of those 35 watt Philips lamps and I have several CDM35/PAR30L/M/FL/3K M130/0 from Mexico lamps in my home and they are almost identical to a halogen par30 without the heat and they do have a slightly longer warm up.. 

No, one uses a 50W ED medium base and the other uses a CDM-TC G12 base. A PAR lamp would not work as it would cast a shadow in the shade. They are table lamps, like you would find on a table beside a couch in a typical living room.

Here is the 50W one. The 35W one is of the same principle only smaller.

Philips lighting Europe, have several Mastercolor compact CMH lamps with spherical arctube that have Ra8>90 for either 3000K and 4200K. One model operates in an unsaturated regime, so the likelihood of expolsion is small. The Powerball of Osram and american Osram Sylvania (Both are Ledvance now) also use this arctube design and have higher CRI than the ones with cylindrical arctube.

What sort of Plastic is the shade made of ? Some PMMA shades have a dye mixed in that does this sort of stuff, and no type of lamp can solve it because it is actual dye and not a color rendering problem

Well, that's one of my theories. I might have to look elsewhere for a better lamp shade.

The lamp in question, a Belgian Philips CDM-T of 35 watts and colour 830 (cylindrical arc tube) is enclosed in a glass globe inside that shade. I am wondering if the glass traps in heat which makes the arc tube run hotter than it should and as a result it raises the colour temperature of the lamp. It seems to me that the quasi-perfect colour happens just at the end of the warmup period, and then the pinkish colour creeps in at the very end.

Then lower the power coming from the ballast. What ballast type is it ?

CMH lamps have vaccum inside the outer jacket, so the arctube won't overheat if the lamp is installed inside an enclosed glass globe.

Both are running on proper electronic ballasts. Since the lamps are rated for enclosed fixtures only, I thought it wouldn't be a problem, however in my search for a solution I thought I'd mention it.

The problem with overheating inside enclosed fixtures, is relevant only to integrated CFLs and LED lamps, where electronics and/or LEDs can overheat and fail sooner inside an enclosed fixtures. Thats I uses CFLs only in my table lamp near my computer, where the CFL mounted base-down without the glass lamp shade.

That's what I thought. I am now focussing on getting a better lamp and a better shade.