Kodak Tri-X vs Ilford HP5+ Film

Introduction

Spending some time with Google shows that there are numerous comparisons between Kodak Tri-X (400TX) and Ilford’s HP5+ film. Are they the same? Are they different? Is one better than the other? On and On and On. Let’s take as objective look as possible between the two emulsions and see what the deal is here.

Cut to the chase

If you don’t want to read any further, and just want a fast answer, then here it is: Kodak Tri-X and Ilford HP5+ are so close to each other that I can say that they are totally, completely, one hundred percent interchangeable. This means that you can shoot and process them exactly the same way in the same chemicals for the same development time. The end result will be close enough that you can’t tell the difference.

The evaluation

We are going to evaluate the two emulsions on two criteria: Tonal range, and granularity.

Tonal range

To evaluate the tonal range, we’ll shoot an 18% grey card on each emulsion, and shoot it from 7 stops under to 11 stops over normal exposure in full stop increments with a studio strobe. The exposure will be set via a Sekonic light meter incident reading and shot through a T-Stop rated lens, with the light meter reading within 0.1 stops of the actual amount of light hitting the grey card. To evaluate the density values for each stop of light, the emulsion will then be digitized with a DSLR using a studio strobe through the same T-Stop rated lens.

From there, the raw captures are evaluated and the average sample value from a 256×256 square in the middle of the scanned frame is calculated. This is done for each emulsion. This will give us a good idea of the density level of the emulsion for a given exposure value.

This is done exactly the same way for each emulsion. The camera position relative to the gray card does not change between each emulsion, and the focal point does not change between each emulsion.

Granularity

For granularity, this is actually pretty straight forward. Look at the scan of the correctly exposed 18% grey card for each emulsion in Adobe Lightroom at 1:1. The scans are just over 4200 dots per inch, which is more than enough resolution to actually digitize individual grains.

Development

To ensure that we’re as close as possible for each emulsion, they’re both developed in Kodak D76 1:1 at 20 degrees Celsius +-0.1 degree in the same daylight tank at the same time for 13:00 with 1 fast inversion every 15 seconds. There was a several minute pre-soak at 20 degrees of the tank/emulsions to get everything up to temperature. A 1:4 vinegar/water stop bath was used to stop development. Both emulsions were fixed in Kodak Fixer for 10:00 with constant agitation.

Concessions

Obviously, this is not up to scientific standards, however, it is within the tolerances that I can bring to bear with the equipment available to me, and I feel that my tolerances are tight enough to use with a reasonable amount of certainty in the results.

Results

Below are the results for each item being evaluated.

Tonal Range

Here is the chart of the two emulsions.

400TX_vs_HP5

When looking at this, there’s a couple of things to remember: It’s not the actual values of each density step that matter because those will vary a bit due to variations in the the power of the strobe firing during the exposures, variations of power of the strobe firing during the scanning, and how many specks of dust and fibers there are on the emulsion in the scanned sample area, which will affect the average calculated sample value. In fact, I’ve repeated this test twice exactly the same way and have even done multiple scanning passes of each emulsion for each test and gotten different but similar results for every single density step. This is the nature of the medium. There’s a lot of moving parts and things that can affect the outcome.

The key takeaway here is the shape of the curve for each emulsion. I’ve included a combined curve that is the average of all the scanning passes of both tests for both emulsions with each end slightly extended beyond sampled values.

In short, both emulsions have the same tone curve and tonal range if developed in the same developer at the same temperature, for the same amount of time and same agitation.

Granularity

OK, what about the grain? I’ll let the image below speak for itself. You can right click on it and download the full image to look at it at full size if you want to look at it really close.

400TX_vs_HP5_grain

So, what are we looking at? A comparison of each emulsion scanned in at 4200+ dpi side by side at 1:1 in Adobe Lightroom. The grain structure is readily evident, and frankly, to me, the two emulsions are close enough in their granularity that at sane enlargement levels, they’re nearly if not completely indistinguishable.

Conclusion

With black and white film, the tonal range and granularity are really only the two things that matter, and as I said in the cut to the chase section, if Tri-X and HP5+ are shot and developed the same way, they’re interchangeable in terms of tonal range and granularity.

Coming in 2017: Simple Film Lab

Photographic film has taken quite a beating in the last decade or so. Film labs have been closing left and right for quite some time now. This is quite unfortunate and something that I’ve struggled with for quite some time myself being as I’m primarily a film photographer.

This led me onto a path of processing and digitizing my own film and developing tools to do so that also give me my images in a way that is complimentary to film.

I’ve finally reached a point where I can offer my services to other film photographers.

A Few Things To Note

You shoot film because of the color and look that you get with it, not because it gives you a lot of resolution or is inexpensive. So with that being said, what do I bring to the table with Simple Film Lab that is better than the other film labs out there? If you look at what other labs charge and what I will be charging, I’m certainly not less expensive from a purely monetary stance. I also won’t really be delivering the highest of resolutions either.

In order to really take advantage of what film has to offer, one must beef up the entire imaging chain. Almost every lab I’ve looked at and tried out typically scans with a Noritsu or Frontier scanner and delivers jpegs. You hear a lot about how a Frontier scanner delivers color like this or that, and how some film scanner is beloved by x type of photographers. OK. I mean no disrespect to other film labs, however, having a process where you deliver jpegs of film scans to customers is not doing the customers or film any favors.

It’s all about the color. While I do have a dedicated 35mm film scanner that is very recent and can scan 35mm film at really high resolutions, and I do have a very high resolution flatbed scanner that can scan 120 film at crazy high resolutions, I also have a way to digitize film using a very controlled light source, with very good optics, and a reasonably high resolution imaging sensor. The setup I prefer could be called a DSLR film scanner, but it’s actually more complicated that than. Photographic film by definition is very high dynamic range, with a lot of color. When you digitize film, what you are essentially doing is taking a picture of the film emulsion. You can take the picture of the film emulsion with a dedicated film scanner, a flatbed scanner, or with a digital or film camera. It’s what you do with the digitized image after that that makes all the difference.

Typically, the color negative is inverted by either the film scanner itself, the scanning software, or manually in Adobe Photoshop. While one can get good results with that, I’ve brought my skills as a computer programmer to bear and developed code that significantly beefs up the entire imaging and color chain after digitizing to full 64 bit floating point in linear color space. What does that even mean? That means the process to turn the color negative into a color positive along with the following color modifications to get a usable image happen in very high resolution 64 bit floating point linear color space. I’d love to be able to deliver 64 bit floating point linear light images to customers, however, that is not something that any software customers would have access to really supports, so the next best thing is 16 bits per sample (or 48 bit) TIFF files in the ProPhoto color space.

Because the high precision digitization workflow requires a calibrated film profile for every film we support digitizing, Simple Film Lab will not accept any film to be processed and digitized. While we can pretty much process any C-41 film (we use standard Kodak C-41 Chemicals), the service we offer is coupled together, so when you send film in, it is to be processed and digitized. The cost therefore, might seem high per roll, but when you factor in that you’re getting processing and a very high quality film scan, and 48 bit TIFF files in the ProPhoto color space as the delivery with enough resolution to make 16×24 prints, it’s worth it, at least we think there’s a market for it.

The Plan

The plan is to start accepting processing orders for Kodak Ektar 100 film in 35mm, and 120 roll the first quarter of 2017, then add Kodak Portra 160, Portra 400, and Portra 800 in 120 roll film in the second or third quarter and add 35mm Portra 160, 400, and 800 later in the year if there is demand for it along with the 4×5 sheet versions at some point in the second half of 2017. We’re also going to keep things simple in terms of what resolutions we offer: There will really only be two options, standard resolution, and custom scan. Standard 2:3 resolution will be 7200×4800 pixels with other aspect ratios having 4800 pixels on the short side, and custom scan is exactly what it sounds like, a custom scan with an output to your specifications. The standard processing/scan target price will be $20 per roll not including shipping, and custom scan will be priced according to how much time/effort Simple Film Lab has to put in. At the end of the day, it all boils down to image processing time and who is spending that time.

All film will always be processed with fresh chemicals, and the target turnaround time will be 5-7 business days. As things pick up, we’ll be adding additional films to the catalog that we support. There are a couple of emulsions that are pretty popular with wedding photographers (Fuji 400H, looking right at you), and we do plan to support it, however, that comes with some challenges, as most labs that cater to processing/scanning that film also use Fuji Frontier scanners and already deliver pretty good results, so in that instance, the biggest issue is going to be getting customers to move away from those labs and start using Simple Film Lab instead.

Additionally, you can expect very good customer service. As my own customer, I have very high standards, and I’m a firm believer in providing very high standards to my customers. Because Simple Film Lab is a small operation, as a customer, you’ll be dealing directly with me, and it will be my eyeballs that look at every single one of your images before they’re sent to you.

In short, Simple Film Lab is the Film Lab that I would want as a customer. Keep watching this space, good things are on the way.