# Acid Base pH vs PhotoMetrix

The clearest difference is price: PhotoMetrix at Free against Acid Base pH's $3.99. PhotoMetrix also leads on update cadence (every 3 weeks vs every 3 months) and iOS requirement (15 vs 17.1). Acid Base pH's advantage is review sentiment (100% vs 67%). On ads, in-app purchases and device support there is nothing between them.

PhotoMetrix is free to download; Acid Base pH costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Acid Base pH ships an update every 3 months, PhotoMetrix every 3 weeks. The most recent releases landed on October 24, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | Acid Base pH | PhotoMetrix |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/acid-base-ph/id977951851/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | **100.0% of reviews** | 66.7% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Monetization | Paid | **Free** |
| Size | 2 MB | 27 MB |
| Requires iOS | 17.1 | **15** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Roman Volinsky](https://appshunter.io/developer/977951850) | [Gilson Augusto Helfer](https://appshunter.io/developer/1131751264) |

## What reviewers say

### Acid Base pH

[App page](https://appshunter.io/ios/app/acid-base-ph/id977951851)

Accurately estimate pH values for acid-base aqueous systems. Calculate pH for weak and strong acids/bases, plot titration curves, and find equivalent points. Export data and find titrant volumes for desired pH.

**Highlights:** Estimate pH of acid-base solutions, Plot titration curves, Find pH and titrant volume at equivalent points, Export titration plots as image or data, Calculate titrant volume for desired pH, Includes list of common indicators

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### PhotoMetrix

[App page](https://appshunter.io/ios/app/photometrix/id1220976347)

This application performs univariate and multivariate data analysis using image acquisition and RGB histograms. It supports various color systems and can export data and charts via email for validation with other software.

**Highlights:** Univariate analysis with Single Linear Correlation, Multivariate analysis with Principal Component Analysis (PCA), Image data acquisition via device camera, RGB histogram conversion, Support for RGB, HSV, HSL, and HSI color systems, Email export of data, analysis, and charts, Calculation of eigenvalues, eigenvectors, scores, and loadings

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Acid Base pH free?

Acid Base pH costs $3.99, with no in-app purchases.

### Is PhotoMetrix free?

PhotoMetrix is free to download, with no in-app purchases.

### Do Acid Base pH or PhotoMetrix have ads?

Neither Acid Base pH nor PhotoMetrix shows ads.

### Which is updated more often, Acid Base pH or PhotoMetrix?

Acid Base pH ships an update every 3 months, and PhotoMetrix every 3 weeks. Most recently, Acid Base pH was updated on October 24, 2026 and PhotoMetrix on October 11, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*