Mango posted part of this thought I'd copy the rest in as it has heaps of great info
from wolfpack1292 on the pinbash forums:
It’s been almost one year since I first posted my LED usage guide and it’s amazing to see how LED technologies and product selections have dramatically changed since then. I decided to write a new usage guide based on the latest and greatest products and my tests and experiences over the past year.
Here are the scenarios and LED bulb type combinations that I use now. Opinions and preferences may vary, but these are my recommendations based on my own experience in converting 25+ pins to LED.
Backbox GI:
My preferred choice for Backbox GI is the new Super Bright LED’s available from Cointaker. I previously used frosted tip single LED’s or 3-bulb LED’s, but the new Super Bright bulbs are brighter and generate a much wider pattern of light.
Color choice is somewhat based on personal preference and in most cases will be dictated by the color scheme of the game or the color choice of GI used on the playfield (i.e. if you use warm white in the playfield GI then should use warm white in the backbox GI to match).
Super Bright, Frosted, and 3 LED bulbs are available in a variety of colors, but typically you will use either warm or cool white. Warm white is often used when the color scheme has a lot of yellows, browns, oranges, light blues, or reds. Cool white works great in dark colored games like BDK (lots of dark blues, greens, purples, blacks, and grays).
If you want to keep the original look and feel of incandescent bulbs, then I highly suggest the warm white Super Bright bulbs. They are almost identical in color to traditional incandescent bulbs and they have by far the best light spread pattern.
If you’re on a budget and still want to save a little cash, then Frosted tip or 3 LED bulbs are a great alternative. I prefer frosted tips over the 3 LED bulbs because they diffuse the light fairly well and they aren't overpowering behind the translite. Frosted tip bulbs are available in both warm or cool white, but the 3-LED bulbs from Pinball Life are only available in cool white.
In most cases you will want to stick with warm white or cool white in the backbox, but colored bulbs can add some very cool effects. For example, you could use colored LED's behind a pair of eyes on the translite to make them stand out or glow a different color. You can also use color changing LED's to give cool effects behind clouds, water, explosions, or titles.
My Preference for Backbox GI
A. Super Bright LED’s
http://www.cointaker.com/category.sc?categoryId=60B1. Frosted Tip Single LED’s (Round Tip)
http://www.cointaker.com/category.sc?categoryId=6B2. Frosted Tip Single LED’s (Flat Tip)
http://www.pinballlife.com/index.php...886&parent=192C. Three Bulb LED’s
http://www.pinballlife.com/index.php...175&parent=192Playfield GI:
There are many factors to consider when choosing an LED bulb for playfield GI lighting. The three biggest factors are color choice, brightness preference, and desired effect. I will start with color choice since color is often the first decision and can sometimes dictate or limit choices in bulb types.
Color Choce:
LED’s suitable for GI are available in a variety of colors, but typically you will use either warm or cool white. Warm white is often used when the color scheme has a lot of yellows, browns, oranges, light blues, or reds. Cool white works great in dark colored games with dark blues, greens, purples, blacks, and grays. Some people prefer the color of traditional incandescent bulbs regardless of the pin color scheme. If this is your preference, then you will want to use a warm white bulb.
You can also use colored LED’s in your GI to accent areas of your playfield or to color match plastics, ramps, artwork, or toys.
Brightness Preference:
Brightness is typically a personal preference, but GI that is too bright can sometimes blind the player or create glare and GI that is too dim can create dark areas in the playfield.
Up until recently there were only two real options. One was to go with 3-LED bulbs for ultimate brightness and the second was to go with frosted tip bulbs to achieve better light diffusion and less brightness. Also, if your color preference was warm white, then your only option was to use single LED frosted tip bulbs because 3-LED bulbs are only available in cool white. The good news is that things have changed quite a bit over the past year and there are now several new bulb types that are ideal for GI applications.
Based on the current lineup of LED bulb types, my personal preference for playfield GI is Super Bright bulbs from Cointaker. These new bulbs are nice and bright and have an outstanding light pattern that closely resembles traditional incandescent bulbs. They are available in both cool and warm white and really look amazing.
If you want to achieve maximum brightness for your GI, then Cointaker offers a new 4-LED bulb. These are available in all colors, including warm and cool white.
Desired Effect:
In most cases you will want to use a standard Super Bright, 3-LED, or Single Frosted Tip LED for your GI (based on your preference). In some cases you can use the same type of bulb for your entire playfield GI. However, some games may require a specific type of bulb to achieve an originally intended effect. A good example of this is the row of blue GI bulbs along the shooter lane in Monster Bash. In this situation you would want to use blue Single Frosted Tip LED’s to achieve the same look and feel as the original incandescent bulbs with blue condoms. I usually try and use rounded frosted tip bulbs whenever the GI bulb is obviously visible and not hidden under a plastic or playfield ramp/toy.
If you like the look and feel of a brighter GI, but do not like the heavy brightness when you play the game, a good tip is to use Single frosted tip LED’s under the sling shots and ball return lanes and then use Super Bright or 3-LED bulbs in the rest of the GI. This will reduce the brightness in the players eyes and will maintain the brighter look and feel throughout the rest of the playfield.
My Preference for Playfield GI
Under Plastics (Normal GI applications)
A. Super Bright LED’s
http://www.cointaker.com/category.sc?categoryId=60B1. Four Bulb LED’s
http://www.cointaker.com/category.sc?categoryId=59B2. Three Bulb LED’s (Only available in cool white)
http://www.pinballlife.com/index.php...175&parent=192Areas where the bulb is obviously visible
A1. Single Frosted Tip Single LED’s (Round Tip)
http://www.cointaker.com/category.sc?categoryId=6A2. Frosted Tip Single LED’s (Flat Tip)
http://www.pinballlife.com/index.php...886&parent=192Playfield Spotlights:
Several new bulb types that are ideal for spot lights have become available in the past year. There are really 3 good bulb options to choose from and it essentially boils down to how much light you need to create. All of the new bulb types are available in all possible colors (including warm white) and it really comes down to personal preference or desired effect.
My personal favorite is the new Ultra Bright bulb from Cointaker. This baby really generates some light and the light is emitted in all directions. The side emitted light is captured by the mirrored spot light and the end result is very nice spot effect. These are by far the best bulbs to use if you need to shine colored light (red, blue, green, etc) onto a specific area or playfield toy. Another positive is that these bulbs have a flat head and stay concealed within the cone of the spotlight.
If the Ultra Bright bulbs are too bright for your taste, then your next best bet is a standard Super Bright bulb. Super Bright bulbs generate a similar spot effect compared to the Ultra bulbs and they also have a flat head that keeps them concealed within the spot light cone.
Another option is to use a 5-way High Power LED or a 4+1 LED. Both bulb types generate a good amount of light and they are designed to shoot light from the top of the bulb and from all 4 sides. These work great in spotlights, but the heads are fairly large and are sometimes noticeable since they can stick out past the end of the spotlight cone.
My Preference for Spot Lights
A. Ultra Bright LED’s
http://www.cointaker.com/category.sc?categoryId=46B. Super Bright LED’s
http://www.cointaker.com/category.sc?categoryId=60C. 5-Way High Power LED’s
http://www.cointaker.com/category.sc?categoryId=9D. 4 + 1 LED’s
http://www.cointaker.com/category.sc?categoryId=13Playfield Inserts:
Inserts from one pin to the next can vary by size, shape, and color. The angle of the lamp socket under each insert can also vary quite a bit. Sometimes the bulb will be angled directly at the insert and sometimes they are parallel to the insert. The ideal type of LED to use can vary from insert to insert and from pin to pin. Your choice really comes down to personal preference and a combination of insert size and socket angle. This is probably the most difficult area to advise on because of all the various scenarios, but I've listed the most common combinations below with recommendations for each one.
Clear White or Clear Yellow inserts - Lamp angle is directed at the insert (not parallel):
Clear white and clear yellow inserts allow a lot of light to pass through and this can often lead to really intense light if a 3 LED or Super Bright bulb is used. The brightness is somewhat limited if there are only 2 or 3 clear white or yellow inserts, but the intensity and brightness can be very overwhelming if the playfield has a lot of these inserts and Super Bright or 3 LED bulbs are used. I usually try and use cool or warm white Single Frosted Tip LED’s in these situations. Single Frosted bulbs deliver good brightness but do not shine too bright to overpower the insert and blind the player.
Recommendation:
Bulb Color = Cool White or Warm White
Small to Medium Insert = Single Frosted Tip LED
Large Insert = Super Bright or 3 LED
Milky White or Milky Yellow inserts - Lamp angle is directed at the insert (not parallel):
If the insert is milky (not clear), then you can use a Super Bright, 3 LED bulb, or single LED bulb. The haziness of the insert will help control the brightness from the stronger bulbs and will also look good with Single Frosted bulbs. If there are a lot of milky white or yellow inserts, then I recommend sticking with Single LED bulbs to help control the brightness.
Recommendation:
Bulb Color = Cool White or Warm White
Small to Medium Insert = Single Frosted Tip LED
Large Insert = Super Bright or 3 LED
Red/Green/Blue/Purple/Orange inserts - Lamp angle is directed at the insert (not parallel):
You can use white bulbs under colored inserts and get good results, but color matching the LED to the insert will give a deeper color and better effect. Using all white is easier and simplifies the ordering process, but color matching gives the best overall effect. If you decide to use white bulbs under some or all of your colored inserts, make sure to use white bulbs for all inserts of the same color. A color matched bulb will definitely give a richer color compared to using a white LED under the same insert. Mixing the two will be very noticeable, so either use all white or use all color matching.
Recommendation:
Bulb Color = The bulb color should match the color of the insert
Small Insert = Single Frosted Tip LED
Medium to Large Insert = Super Bright or 3 LED
All inserts where the lamp socket is flat angled or parallel to the insert:
If the lamp socket is at a flat angle or parallel to the insert then you need a bulb that angles the light up and toward the insert. There were not a lot of good choices for these types of applications in the past, but Cointaker has recently released a bendable Super Bright bulb that works extremely well in these situations. The LED lens is connected to a set of bendable wires that extend from the bulb base. This allows you to bend and angle the LED lens directly at the insert.
Recommendation:
Bulb Color = Use the same color recommendations provided in the three previous insert sections
Small, Medium, and Large Insert = Flexible Super Bright
http://www.cointaker.com/category.sc?categoryId=60Flashers:
Some flashers are directional (all the light is angled straight away from the top of the bulb) and some flashers have bulbs on the top and sides of the bulb. Most flasher applications can use the straight away flasher because the bulb will be angled into a flasher lens cap or toward the insert or translite. However, sometimes you may need to use a flasher that has LED's on the side because the flasher will lay parallel to the insert or under a plastic and you need the light to shoot in all directions.
I usually color match my flashers to the insert color or lens cap, and I sometimes color match them to the playfield area or plastic covering. You can also use colored flashers under white inserts to add different effects.
My Recommendations
A. Cointaker Flashers (Most affordable and they emit Light from the top and sides of the flasher)
http://www.cointaker.com/category.sc?categoryId=8B. Pinball Life Flashers (Good quality, but light is primarily directed straight up from the top of the bulb).
http://www.pinballlife.com/index.php...arent=192&pg=1Pop Bumpers:
For Pop Bumpers you want to use an LED bulb that emits light in a wide pattern to fill up the entire pop bumper cap with light. I typically choose from one of two bulb types for pop bumpers and sometimes the choice is dictated by the type of pop bumper cap and the clearance available for the bulb when the cap is installed. Super Bright LED’s are great when the space between the socket and the bottom of the cap is shallow. These bulbs are bright and have a great light spread to fill up the pop cap. The other choice (if you have enough clearance) is a 4 + 1 LED bulb. The 4 + 1 bulb has 1 high power LED that shoots light up and 4 regular powered LED’s that shoot light out the sides. These create a good effect in pop bumpers but cannot always be used due to clearance issues.
Recommendation:
Bulb Color = The bulb color should match the color of the Pop Cap
Shallow Clearance Situations: Super Bright LED’s
http://www.cointaker.com/category.sc?categoryId=60Regular Clearance: 4 + 1 LED’s
http://www.cointaker.com/category.sc?categoryId=13 
