Kodak Wratten Filter Reference Chart

Wratten
number
Visible color Filter factor
or alternate designation
F-Stops correction Uses and characteristics
1A       Called a skylight filter, this absorbs ultraviolet radiation, which reduces haze in outdoor landscape photography.
2A pale yellow     Absorbs ultraviolet radiation. longpass filter blocking wavelengths below 405 nm
2B pale yellow     Absorbs ultraviolet radiation, slightly less than #2A. longpass filter blocking wavelengths below 395 nm
2C       Absorbs ultraviolet radiation. longpass filter blocking wavelengths below 390 nm
2E pale yellow     Absorbs ultraviolet radiation, slightly more than #2A. longpass filter blocking wavelengths below 415 nm
3 light yellow     Absorbs excessive sky blue, making sky look slightly darker in black and white images. longpass filter blocking wavelengths below 440 nm
4 yellow     longpass filter blocking visible wavelengths below 455 nm
6 light yellow K1   not a longpass filter
8 yellow K2 1 Absorbs more blue than #3. longpass filter blocking visible wavelengths below 465 nm
9 deep yellow K3   Absorbs more blue than #8. longpass filter blocking visible wavelengths below 470 nm
11 yellowish-green X0 2 Color Correction. not a longpass filter
12 deep yellow Minus blue 1.3 Minus blue filter; complements #32 minus-green and #44A minus-red. Used with Ektachrome or Aerochrome Infrared films to obtain false-color results. Used in ophthalmology and optometry in conjunction with a slit-lamp and a cobalt blue light to improve contrast when assessing the health of the cornea and the fit of contact lenses. longpass filter blocking visible wavelengths below 500 nm
13 Green   2 Color Correction. not a longpass filter
15 deep yellow G 1.6 Darkens the sky in black and white outdoor photography. longpass filter blocking visible wavelengths below 510 nm
16 yellow-orange   1.6 Performs like #15, but more so; longpass filter blocking visible wavelengths below about 520 nm
18A visually opaque     Based on Wood's glass, transmits small bands of ultraviolet radiation and infrared radiation.
18B very deep violet     Similar to 18A but with wider bands of transmittance in both the ultraviolet and infrared, a less 'pure' filter.
21 orange   2 Contrast filter for blue and blue-green absorption. longpass filter blocking visible wavelengths below 530 nm
22 deep orange   2.3 Contrast filter, greater effect than #21. longpass filter blocking visible wavelengths below 550 nm
23A light red     longpass filter blocking visible wavelengths below 550 nm
24 red     Used for color separation of Kodachrome transparency film, complements #47B and #61. longpass filter blocking visible wavelengths below 575nm. Red for 'Two Color Photography' (daylight or tungsten). White flame arc tri-color projection.[5]
25 red tricolor A 3 Used for color separation and infrared photography longpass filter blocking below 580 nm.
26 red     longpass filter blocking below 585 nm
29 deep red F 4 Used for color separation, complements #47 and #61. In black and white outdoor photography makes blue skies look very dark, almost black. In infrared photography, blocks much visible light, increasing the effect of the infrared frequencies on the picture. longpass filter blocking below 600 nm.
32 magenta     Minus-green. Complements #12 minus-blue and #44A minus-red.
33 magenta     Contrast filter for strongest green absorption. For photomechanical color masking.
34A violet     Used for minus-green and plus-blue separation.
38A blue     Absorbs red, some UV and some green light.
40 light green     Green, for two color photography (tungsten).
44 light blue-green     minus-red filter with much UV absorption.
44A light blue-green     minus-red, complements #12 is minus-blue and #32 minus-green.
47 blue tricolor C5   Used for color separation. Complements #29 and #61.
47A light blue     By removing lots of light that is not blue, blue and purple objects show a broader range of colors. Used for medical applications that involve making dyes fluoresce.
47B deep blue tricolor     Used for color separation. It is also commonly used to calibrate video monitors while using SMPTE color bars.[6]
50 deep blue      
56 light green      
57 green     Green for 'Two Color Photography' (daylight).
58 green tricolor B   Color separation.
60 green     Green for two color photography' (tungsten).
61 deep green tricolor N   Color separation, complements #29 and #47.
70 red     Used for color separation and infrared photography longpass filter blocking below 650 nm.
74 dark green monochromat     Transmits 10 percent of green radiation and virtually no yellow radiation from mercury-vapor illumination.
80A blue 4 2 Color Conversion. Raises the color temperature, causing a 3200 K tungsten-lit scene to appear to be daylight lit, approximately 5500 K. This allows use of a daylight balanced film with tungsten lighting.
80B blue 3 1+2/3 Similar to 80A; 3400 K to 5500 K.
80C blue 2 1 Similar to 80A; 3800 K to 5500 K. Typically used so that old-style flashbulbs can be used on a daylight film.
80D blue 1.5 1/3 Similar to 80A; 4200 K to 5500 K.
81A pale orange 1.4 1/3 Warming filter to decrease the color temperature slightly; this can also be used when shooting tungsten type B film (3200 K) with 3400 K photoflood lights. The opposite of 82A.
81B pale orange 1.4 1/3 Warming filter, slightly stronger than 81A. The opposite of 82B.
81C pale orange 1.5 1/3 Warming filter, slightly stronger than 81B, opposite of 82C.
81D pale orange     Warming filter, slightly stronger than 81C.
81EF pale orange   1/3 Warming filter, stronger than 81D.
82A pale blue 1.3 1/3 Cooling filter to increase the color temperature slightly. The opposite of 81A.
82B pale blue 1.4 2/3 Cooling filter, slightly stronger than 82A and opposite of 81B. Can also be used when shooting tungsten type B film (3200 K) with household 100 W electric bulbs (2900 K).
82C pale blue 1.5 2/3 Cooling filter, slightly stronger than 82B and opposite of 81C.
85 amber 1.5 2/3 Color conversion, the opposite of the 80A; this is a warming filter that takes an outdoor scene lit by sunlight (which has a color temperature around 5500 kelvins) and makes it appear to be lit by tungsten incandescent bulbs around 3400 K. This allows an indoor balanced film to be used to photograph outdoors. These filters were used in Super 8 movie cameras that were designed to use Tungsten film.
85B amber 1.5 2/3 Similar to 85; converts 5500 K to 3200 K.
85C amber 1.5   Similar to 85; converts 5500 K to 3800 K.
85N3 amber     Neutral density of 1 stop + color conversion, the opposite of the 80A; this is a warming filter that takes an outdoor scene lit by sunlight (which has a color temperature around 5500 kelvins) and makes it appear to be lit by tungsten incandescent bulbs around 3400 K. This allows an indoor balanced film to be used to photograph outdoors.
85N6 amber     Neutral density of 2 stops + color conversion, the opposite of the 80A; this is a warming filter that takes an outdoor scene lit by sunlight (which has a color temperature around 5500 kelvins) and makes it appear to be lit by tungsten incandescent bulbs around 3400 K. This allows an indoor balanced film to be used to photograph outdoors.
85N9 amber     Neutral density of 3 stops + color conversion, the opposite of the 80A; this is a warming filter that takes an outdoor scene lit by sunlight (which has a color temperature around 5500 kelvins) and makes it appear to be lit by tungsten incandescent bulbs around 3400 K. This allows an indoor balanced film to be used to photograph outdoors.
87 opaque     Passes infrared but not visible frequencies. blocks wavelengths below 740 nm
87A opaque     Passes infrared but not visible frequencies. blocks wavelengths below 880 nm
87B opaque     Passes infrared, blocks visible frequencies. blocks wavelengths below 820 nm
87C opaque     Passes infrared, blocks visible frequencies. blocks wavelengths below 790 nm
88 opaque     Passes infrared, blocks visible wavelengths below 700 nm.
88A opaque     Passes infrared, blocks visible frequencies. below 720 nm.
89B near-opaque red R72   Passes infrared, longpass filter blocking visible wavelengths below 690 nm (very deep red).  Aerial photography is one use.
90 dark grayish amber     Used for viewing scenes without color before photographing them, in order to assess the brightness values. Not used for actual photography.
92 red     color densitometry. longpass filter blocking visible wavelengths below 625 nm
93 green     color densitometry.
94 blue     color densitometry.
96 gray varies   neutral density filter. Blocks all frequencies of visible light approximately evenly, making scene darker overall. Available in many different values, distinguished by optical density or by filter factor.
98 blue     Like a #47B plus a #2B filter.
99 green     Like a #61 plus a #16 filter.
102 yellow-green     Color conversion; makes a barrier-level type photocell respond as a human eye would.
106 amber     Color conversions; makes an S-4 type photocell respond as a human eye would.

ADDITIONAL WRATTEN FILTER TIPS

Wratten 96 ND Chart

.3 +1 stop

.6 +2 stops

.9 +3 stops

1.2 + 4 stops

1.5 + 5 stops

1.8 + 6 stops

2.1 + 7 stops

2.4 + 8 stops

2.7 + 9 stops

3.0 + 10 stops 

YouTube Video - How To Cut Wratten Filters Down To Lee Filter Size

ND FILTER EXPOSURE COMPENSATION EXAMPLES
I rate Ilford HP5 film at EI 250 and using the above ND filters.

I can extend the exposure times as indicated below.

1/250 (0)
1/125 (+1) .3
1/60 (+2) .6
1/30 (+3) .9
1/15 (+4) 1.2
1/8 (+5) 1.5
1/4 (+6) 1.8
1/2 (+7) 2.1
1s (+8) 2.4
2s->3s (+9) 2.7
4s-> 7s (+10) 3.0

I rate Ilford FP4 film at EI 125 and using the above ND filters.

I can extend the exposure times as indicated below.

1/125 (0)
1/60 (+1) .3
1/30 (+2) .6
1/15 (+3) .9
1/8 (+4) 1.2
1/4 (+5) 1.5
1/2 (+6) 1.8
1s (+7) 2.1
2s-> 3s (+8) 2.4
4s -> 4s (+9) 2.7
8s -> 19s (+10) 3.0


FP4/HP5 Reciprocity
2s ->3s
4s ->7s
8s ->19s
12s->33s
16s->50s
24s->93s (1.5 min)
32s->145s
45s->250s (4.1 min)
60s->378s (6.3 min)
90s->853s (14.25 min)
120s->1670s (30 min)