Exposing Aerochrome: ISO & Metering

Accurate exposure is crucial due to Aerochrome’s limited dynamic range. Setting your ISO correctly will also be determined by how you want to develop your roll. Either E-6 Processing or C-41 Processing Consider the following recommendations:

Although Aerochrome is rated at ISO 400, my tests suggest that this batch may have lost some sensitivity over time. To evaluate this, I conducted a six-shot exposure bracket test using a color chart at ISO 400, capturing normal exposure, +1 stop, +2 stops, -1 stop, and -2 stops. From these tests, I found that the +1 and +2 stop exposures looked best, indicating that the film has likely lost around ½ to 1 stop of sensitivity. However, given how infrared film reacts to light differently than standard stocks, gauging sensitivity loss isn’t always straightforward.

One of the most significant findings from my tests was related to TTL metering recommendations from online guides. Most Aerochrome guides state that ISO 400 already assumes the use of a Yellow #12 filter, meaning that no additional compensation should be needed. Which is correct, in some ways but this can be confusing! The ISO 400 does already account for a Yellow filter. However, when metering through the lens with TTL metering and a filter attached, the results on my first test rolls appeared underexposed. This makes sense because the meter is seeing reduced light through the filter and compensating, So I was effectively underexposing the film stock. When I first read this my knowledge told me to question this, but since it was my first rodeo with Aerocrhome I tried it out and although the results weren’t horrible It was definitely underexpose.

To correct this, I found when using my in camera meter I just need to adjust my ISO setting to compensate for the filters light loss, which did the trick! With the Yellow #12 or #15 for example Setting my ISO at 200 (E-6) or ISO 160 (C-41) produced much better results. Now some images still looked good when I rated at ISO 400 (E6) or ISO (C-41) some of this I think depended on the lighting in my environment I was shooting at the time. The most consistent and balanced results came from lowering the ISO to compensate for how the TTL meter was reading the scene as well as the loss of sensitivity. This is just a recommendation based on my findings and experience, but I’d encourage others to test their own setups and see what works best.

Below I have done the dirty work for you and listed the Filters, Light Loss (Filter Factor) and Recommended ISO

See our test images below for reference.

ISO Settings

• E-6 Processing: ISO 400

• C-41 Processing: ISO 320

  READ BELOW FOR MORE DETAILS BASED ON YOUR CAMERA, FILTER CHOICE, & HOW YOU WILL METER

Filter Compensation ( TTL Metering)

• Yellow #12: Light loss: 1 stop / Recommended ISO (TTL Metering): ISO 200

• Yellow #15: Light loss: 1.3 stops / Recommended ISO (TTL Metering): ISO 160

• Orange #16: Light loss: 1 2/3 stops / Recommended ISO (TTL Metering): ISO 125-160

Note: Light loss varies slightly between filter brands. We used Tiffen filters, Users should check their brand of filters light loss although in theory they should be the same.

metering techniques

To meter a scene with Aerochrome, it's best to use spot metering and take a reading from the brightest green foliage in your composition. Adjust your exposure so that these leaves are placed at neutral gray (0 EV) on your meter, ensuring that they render properly in the infrared spectrum without washing out or turning too dark.

If your camera doesn’t have spot metering, center-weighted metering is the next best option. Many TTL meters in film cameras are center-weighted, meaning they prioritize the exposure reading from the central portion of the frame while still factoring in surrounding areas. When using center-weighted metering, be mindful of elements like the sky or deep shadows, as they can skew the exposure. If the scene has a lot of bright sky, tilt your camera slightly downward to exclude it while metering, then lock the exposure before recomposing your shot.

For best results, consider bracketing by taking one shot at the metered setting, one slightly overexposed (+1 stop), and one slightly underexposed (-1 stop) or you can meter the brightest portion and the darkest portion and pick an apeture or shutter speed in the middle to balance your exposure and not waste frames from bracketing.

TTL (Through-the-Lens) Metering

• If your camera meters through the filter, lower ISO to compensate for the light loss of the filter and prevent underexposure:

  • Yellow #12: Set ISO 200 for (E-6) ISO 160 for (C-41)

  • Yellow #15: Set ISO 160 for (E-6) ISO 125 for (C-41)

  • Orange #16: Set ISO 125 for (E-6) ISO 100 for (C-41)

  If you have a camera that does is not TTL and does not meter through the filter then follow the Standard ISO 400 (E-6) ISO 320 (C-41)

Handheld Metering

• Metering Through the Filter: lower ISO to compensate for the light loss of the filter and prevent underexposure:

  • Yellow #12: Set ISO 200 for (E-6) ISO 160 for (C-41)

  • Yellow #15: Set ISO 160 for (E-6) ISO 125 for (C-41)

  • Orange #16: Set ISO 125 for (E-6) ISO 100 for (C-41)

Lighting Considerations

• Avoid backlit scenes to prevent contrast issues.

• Best results in full sunlight to enhance infrared reflection. although you can shoot in overcast depending on your scene and what you are shooting