Value Study vs Calibration Flow

In art, value (or tone) refers to how light or dark a colour is. If you're learning to paint or draw, doing value studies is one of the best ways to improve. These small, loose sketches in greyscale help you understand where shadows fall and highlights appear—essential for capturing depth and form. Value Study is a simple, focused tool designed to help you see values more clearly in your reference images. Instead of just converting a photo to black and white, this app lets you break down tones step by step. Start with just black and white to map out the biggest shapes, then gradually add more values to refine your understanding. You can also highlight all areas of an image that share the same value, making it easier to see subtle shifts in tone. This is especially useful in complex references, like portraits, where different parts of the image might have the same level of shadow but look completely different in colour. Value Study isn’t here to replace traditional studies—it’s here to enhance them. Whether you're sketching, painting, or working digitally, this tool makes it easier to focus on the fundamentals of light, shadow, and form. Try it for free with all features enabled on sample images from Unsplash before deciding to unlock the full app with a low-cost yearly or lifetime purchase. All Value Study Pro upgrades count as lifetime purchase. Either option will unlock Value Study across iPhone, iPad and Mac. Annual: Auto-renews yearly. Lifetime: One-time payment, no fees. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Calibration Flow is the tonal calibration tool for silver-based and alternative photographic processes: cyanotype, platinum-palladium, gum bichromate (Aquaprint), carbon, Van Dyke, resinotype. KEY FEATURES • Custom calibration curves per process, paper and negative • Pre-calibration sheet: compare 12 settings per exposure time and refine your choice with 9 variants; crop library photos while preserving the original. • Digital negative: high-resolution generation and export (300 to 720 dpi, continuous tones or halftones) • Direct printing: send the negative to your printer from the app, with no AirPrint and no third-party app — it asks the machine what it can do before sending, honors its hardware margins, and follows the job • CMYK tonal separation with black generation control (GCR), including multi-zone • Full Gamut color mode with 5, 6 and 7 channels (Orange, Green, Violet), to go beyond simple CMYK • Ink steps: set where each ink stops, in negative as well as positive, combinable with zones • Screen angles: one angle per ink (rosette) or all aligned • Color Venn: printing test target and ink-layer overlay simulator, with eyedropper and magnifier • .acv export for Photoshop, Lightroom, Affinity Photo and GIMP • Registration marks: a frame of targets around the image and a mini-target that follows the output, in negative as well as positive • Harmonic exposure timer with circular dial, multi-device sync, and Dynamic Island / Live Activity on iPhone • Bluetooth control for compatible UV lamps (BanlanX SP630E controller) — on/off control from the app, no variable-intensity dimming • HD media library with cloud sync and multi-device access • Large-format tiling: edge-to-edge A4, A3 and A3+ sheet assembly PRO SUBSCRIPTION Calibration Flow is free with: – 3 cloud-synced calibration curves – 300 MB of cloud storage – Unlimited presets – CMYK tonal separation (4 inks) The Pro subscription unlocks: – Unlimited calibration curves – 5 GB of cloud storage – .acv export (Photoshop) – Color mode with extended inks (5 to 7) – Advanced separation settings: black generation, fine tuning Two plans: €9.90/month, or €99/year (equivalent to €8.25/month, effectively 2 months free). Auto-renewing, cancel anytime in your Apple account Settings. Your subscription works across all your Picturale devices. Calibration Flow is part of the Picturale ecosystem, dedicated to silver-based photographic processes and non-toxic photography. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Calibration Flow Terms: https://calibrationflow.com/cgu