#### Table I

Observed and calculated visual transmissions, foveal.Observations with a 1-degree field, fixated within the fovea, and exposed for 1 second. Calculated visual transmissions, (T_{υ}), are based on foveal values of relative sensitivity (K_{λ}) taken from Fig. 4, and on the energy distribution of a black body at 3200°K. λ_{max} is the wave-length of maximum spectral visual transmission of each filter (Fig. 3). In the designations of the filters, J = Jena, C = Corning, and EBH designates a special group of infra-red filters manufactured by the Polaroid Corporation.

Filter | JRG-8 plus C 3961 | C 2600 | EBH 3 | EBH 5–27 |
---|

λ_{max} | 685 | 725 | 835 | 873 |

No. of observers | 54 | 48 | 39 | 54 |

I. Calc. log T_{υ} relative to 685 mμ filter | 0.00 | +0.03 | −3.30 | −3.90 |

II. Obs. log T_{υ} relative to 685 mμ filter | 0.00 | −0.09 | −3.23 | −3.91 |

III.
$$log\frac{\text{calculated}}{\text{observed values}}(\text{I}-\text{II})$$ | 0.00 | +0.12 | −0.07 | +0.01 |

#### Table II

Observed and calculated visual transmissions, peripheral.Observations made with a 1-degree field, fixated 8 degrees above the fovea and exposed for one second. Source at 3200°K; 2 cm of water in light path. Otherwise as in Table I.

Filter | JRG=8 plus C 3961 | C 2600 | EBH 3 | EBH 5–27 |
---|

λ_{max} | 685 | 725 | 838 | 874 |

No. of observers | 54 | 48 | 39 | 54 |

I. Obs. log T_{υ} relative to 685 mμ filter | 0.00 | +0.02 | −3.07 | −3.68 |

II. Calc. log T_{υ} based on Goodeve’s sensitivity function | 0.00 | +0.01 | −3.27 | −4.01 |

III. Discrepancy (I minus II) | 0.00 | +0.01 | +0.20 | +0.33 |

IV. Calc. log T_{υ} based on corrected sensitivity function | 0.00 | +0.09 | −3.10 | −3.62 |

V. Discrepancy (I minus IV) | 0.00 | −0.07 | +0.03 | −0.06 |

#### Table III

Variation, with respect to wave-length, of the ratio between foveal and peripheral thresholds in the red and infra-red.Measurements with the adaptometer described in text, using a 1-degree field and 1-second exposures. Peripheral fields fixated 8 degrees above the fovea.

Filter | JRG-8 plus C 3961 | C 2600 | C 2540 plus C 2600 | EBH 3 | EBH 5–27 | EBH 5–36 |
---|

λ_{max} | 685 | 725 | 762 | 835 | 873 | 908 |

No. of observers | 54 | 48 | 10 | 39 | 54 | 4 |

$$log\frac{\text{peripheral threshhold}}{\text{foveal threshhold}}$$ | +0.04 | −0.08 | −0.08 | −0.16 | −0.20 | −0.34 |

#### Table IV

Observed and calculated visual transmissions, peripheral.Data from 11 observers, using a 7-degree field, fixated peripherally and exposed for 1 second.

Filter | EBH 5–36 | EBH 5–8 | EBH 5–14 |
---|

λ_{max} | 908 | 928 | 944 |

I. Obs. log T_{υ} relative to 873 mμ filter | −0.75 | −1.18 | −1.44 |

II. Calc. log T_{υ} relative to 87.3 mμ filter, based on corrected sensitivity function | −0.76 | −1.14 | −1.46 |

Discrepancy (I minus II) | +0.01 | −0.04 | +0.02 |

#### Table V

Spectral sensitivity (K_{λ}) in the red and infra-red. Values selected as described in the text, for 1° test fields, exposed for 1 second, and fixated either within the fovea or 8° above the fovea in the wholly dark-adapted eye. The foveal values beyond 750 mμ are identical with those of Goodeve (1936). All spectral sensitivities are stated relative to the maximum sensitivity of the fovea, here taken as 1 (logK_{λ} =0.0); on this basis the maximum sensitivity of the peripheral area, at 505 mμ. is 363 (logK_{λ}=2.56).

Wavelength (mμ) | 1° oveal field | 1° field fixated 8° above fovea |
---|

logKλ | K_{λ} | logK_{λ} | K_{λ} |
---|

700 |
$$\overline{3}.55$$ | 3.55×10^{−3} |
$$\overline{3}.53$$ | 3.4×10^{−3} |

710 |
$$\overline{3}.23$$ | 1.7 |
$$\overline{3}.23$$ | 1.7 |

720 |
$$\overline{4}.92$$ | 8.3×10^{−4} |
$$\overline{4}.92$$ | 8.3×10^{−4} |

730 |
$$\overline{4}.61$$ | 4.1 |
$$\overline{4}.63$$ | 4.3 |

740 |
$$\overline{4}.31$$ | 2.0 |
$$\overline{4}.34$$ | 2.2 |

750 |
$$\overline{4}.02$$ | 1.04 |
$$\overline{4}.06$$ | 1.15 |

760 |
$$\overline{5}.71$$ | 5.1×10^{−5} |
$$\overline{5}.78$$ | 6.0×10^{−6} |

770 |
$$\overline{5}.43$$ | 2.7 |
$$\overline{5}.51$$ | 3.2 |

780 |
$$\overline{5}.15$$ | 1.4 |
$$\overline{5}.25$$ | 1.8 |

790 |
$$\overline{6}.87$$ | 7.4×10^{−6} |
$$\overline{6}.99$$ | 9.8×10^{−6} |

800 |
$$\overline{6}.59$$ | 3.9 |
$$\overline{6}.73$$ | 5.4 |

810 |
$$\overline{6}.34$$ | 2.2 |
$$\overline{6}.48$$ | 3.0 |

820 |
$$\overline{6}.08$$ | 1.2 |
$$\overline{6}.23$$ | 1.7 |

830 |
$$\overline{7}.83$$ | 6.8×10^{−7} |
$$\overline{7}.99$$ | 9.8×10^{−7} |

840 |
$$\overline{7}.57$$ | 3.75 |
$$\overline{7}.76$$ | 5.75 |

850 |
$$\overline{7}.34$$ | 2.2 |
$$\overline{7}.53$$ | 3.4 |

860 |
$$\overline{7}.11$$ | 1.3 |
$$\overline{7}.32$$ | 2.1 |

870 |
$$\overline{8}.88$$ | 7.5×10^{−8} |
$$\overline{7}.11$$ | 1.3 |

880 |
$$\overline{8}.65$$ | 4.5 |
$$\overline{8}.90$$ | 7.9×10^{−8} |

890 |
$$\overline{8}.45$$ | 2.8 |
$$\overline{8}.71$$ | 5.1 |

900 |
$$\overline{8}.23$$ | 1.7 |
$$\overline{8}.52$$ | 3.3 |

910 |
$$\overline{8}.03$$ | 1.07 |
$$\overline{8}.35$$ | 2.2 |

920 |
$$\overline{9}.83$$ | 6.6×10^{−9} |
$$\overline{8}.17$$ | 1.5 |

930 |
$$\overline{9}.62$$ | 4.2 |
$$\overline{8}.00$$ | 1.0 |

940 |
$$\overline{9}.43$$ | 2.7 |
$$\overline{9}.82$$ | 6.6×10^{−9} |

950 |
$$\overline{9}.24$$ | 1.7 |
$$\overline{9}.65$$ | 4.5 |

960 |
$$\overline{9}.05$$ | 1.1 |
$$\overline{9}.48$$ | 3.0 |

970 |
$$\overline{10}.87$$ | 7.4×10^{−10} |
$$\overline{9}.31$$ | 2.0 |

980 |
$$\overline{10}.69$$ | 4.9 |
$$\overline{9}.14$$ | 1.4 |

990 |
$$\overline{10}.51$$ | 3.2 |
$$\overline{10}.98$$ | 9.55×10^{−10} |

1000 |
$$\overline{10}.34$$ | 2.2 |
$$\overline{10}.82$$ | 6.6 |

1010 | | |
$$\overline{10}.66$$ | 4.6 |

1020 | | |
$$\overline{10}.51$$ | 3.2 |

1030 | | |
$$\overline{10}.35$$ | 2.2 |

1040 | | |
$$\overline{10}.19$$ | 1.55 |

1050 | | |
$$\overline{10}.04$$ | 1.1 |