Comparison of 12 Ilford and Kodak Unhypered B&W Films

The Top 5 Unhypered Ilford and Kodak B&W Films
(Tested With a Two Minute Exposure)
FILM	FILM CODE	ISO	2 MIN F/STOP LOSS	P FACTOR	2 MINUTE ISO	COMMENTS
Ilford HP 5+	(none)	400	1.18	0.83	183	1st best B&W film
Kodak T400CN	CN	400	.67	0.90	266	2nd best B&W film
Kodak T-MAX 400	TMY	400	1.33	0.81	167	3rd best B&W film
Kodak Tri-X	TX	400	1.67	0.76	133	4th best B&W film
Kodak T-Max 3200	TMZ	3200	2.33	0.67	667	5th best B&W film

The 2 MIN F/STOP LOSS refers to how much sensitivity in F/stops the film lost in a comparison of a normally illuminated 1/8th sec exposure compared to a 128 second exposure at the same illumination level taken through a 1000X (10 F/stop ND 3.0) neutral density filter. (These two exposures are theoretically equal.)

The P FACTOR is the film's Swartzchild exponent used for measuring reciprocity law failure with the formula P=1-(s/7) where "s" is the speed loss in F/stops over a given exposure length.

The 2 MIN ISO is the film's AVERAGE ISO speed over a two minute exposure, accounting for reciprocity law failure, and rounding to the nearest 1/3 F/stop.

Ilford HP 5+ was chosen as the best unhypered B&W film because of its good red and blue sensitivity and moderate reciprocity law failure. Although Kodak's T400CN aparently has similar color response with better reciprocity characteristics, T400CN possesses lower overall image contrast.

NOTE:These film preference recomendations are simply MY OWN opinion based on the limited and somewhat unscientific comparison described here. They are listed only as a suggestion of which films may be worth further star testing with an individual's particular astrophotographic setup.

*** To see these images at their best, adjust your monitor to distinctly show all the gray steps in this step wedge. ***
Step wedge courtesy of Chuck Vaughn

Blue, Green, and Red response For Ilford and Kodak B&W Films

Blue = 470 nanometers, Green = generic LED, Red = 660 nanometers

These images were taken in a light-proof box which allowed me to expose a white test target illuminated by blue, green, and red LEDs. Each color's target was partitioned from the adjacent color and ruled at one-inch intervals. The LEDs illuminated the target from the left side and the degree of film sensitivity in each color can be compared by reading the faintest scale visible. All exposures were two minutes at f/2.8 taken with a Nikon F and a 50 mm f/1.4 Nikor lens. All films were developed in the same developer according to manufacturer's specifications. The images were scanned with an HP PhotoSmart scanner. This scanner works well for most applications, but it really hates large black areas on color slides, so the background on some images way be mushy.

NOTE: These images can only be used for comparing one film against another. The LED brightness is not calibrated and the target scale divisions do not represent hard numerical data about any specific film.

Comparison of All 12 Unhypered Ilford and Kodak B&W Films
(Tested With a Two Minute Exposure)
FILM	FILM CODE	ISO	2 MIN F/STOP LOSS	P FACTOR	2 MINUTE ISO	COMMENTS
Ilford Pan F	(none)	50	1.67	0.76	17	Not recomended
Kodak T-MAX 100	TMX	100	1.33	0.81	33	Not recomended
Ilford FP 4+	(none)	125	1.50	0.79	47	Not recomended
Kodak Plus-X	PX	125	2.0	0.71	31	Not recomended
Kodak Technical Pan	TP	125	1.67	0.76	41	Not recomended
Ilford SFX	(none)	200	2.67	0.62	33	Not recomended
Ilford XP-2	(none)	400	1.0	0.86	200	Acceptable
Ilford HP 5+	(none)	400	1.18	0.83	183	1st best B&W film
Kodak T400CN	CN	400	0.67	0.90	266	2nd best B&W film
Kodak T-MAX 400	TMY	400	1.33	0.81	167	3rd best B&W film
Kodak Tri-X	TX	400	1.67	0.76	133	4th best B&W film
Kodak T-MAX 3200	TMZ	3200	2.33	0.67	667	5th best B&W film

Unhypered Ilford and Kodak B&W Films Compared by Characteristic
(Best at the Top, Ranked in Descending Order)
RANK	INITIAL ISO	2 MIN ISO	2 MIN F/STOP LOSS	RED SENSITIVITY	GREEN SENSITIVITY	BLUE SENSITIVITY
1	T-MAX 3200	T-MAX 3200	T400CN	Technical Pan	T-MAX 400	T400CN
2	HP 5+	T400CN	XP-2	SFX	T400CN	XP-2
3	T400CN	XP-2	HP 5+	HP 5+	Tri-X	Tri-X
4	T-MAX 400	HP 5+	T-MAX 400	T-MAX 400	HP 5+	HP 5+
5	Tri-X	T-MAX 400	T-MAX 100	T400CN	T-MAX 3200	T-MAX 400
6	XP-2	Tri-X	FP 4+	Tri-X	XP-2	Plus-X
7	SFX	FP 4+	Tri-X	T-MAX 3200	Plus-X	Pan F
8	Plus-X	Technical Pan	Technical Pan	XP-2	FP 4+	FP 4+
9	Technical pan	T-MAX 100	Pan F	Plus-X	T-MAX 100	T-MAX 3200
10	FP 4+	SFX	Plus-X	FP 4+	Pan F	SFX
11	T-MAX 100	Plus-X	T-MAX 3200	T-MAX 100	SFX	T-MAX 100
12	Pan F	Pan F	SFX	Pan F	Technical Pan	Technical Pan

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Comparison of 12 Ilford and Kodak Unhypered B&W Films

The Top 5 Unhypered Ilford and Kodak B&W Films (Tested With a Two Minute Exposure)

Ilford HP 5+ was chosen as the best unhypered B&W film because of its good red and blue sensitivity and moderate reciprocity law failure. Although Kodak's T400CN aparently has similar color response with better reciprocity characteristics, T400CN possesses lower overall image contrast.

Blue, Green, and Red response For Ilford and Kodak B&W Films

Blue = 470 nanometers, Green = generic LED, Red = 660 nanometers

Comparison of All 12 Unhypered Ilford and Kodak B&W Films (Tested With a Two Minute Exposure)

Unhypered Ilford and Kodak B&W Films Compared by Characteristic (Best at the Top, Ranked in Descending Order)

The Top 5 Unhypered Ilford and Kodak B&W Films
(Tested With a Two Minute Exposure)

Comparison of All 12 Unhypered Ilford and Kodak B&W Films
(Tested With a Two Minute Exposure)

Unhypered Ilford and Kodak B&W Films Compared by Characteristic
(Best at the Top, Ranked in Descending Order)